Update 2.40pm: Theresa May has said she expects senior Football Association officials will want to be "considering their position" over attending the World Cup in Russia.
The British Prime Minister said any decision over attendance is one for the sporting authorities, although reiterated that no ministers nor members of the Royal Family will visit the football tournament this summer.
England will face Belgium, Panama and Tunisia in the group stages of the competition, which begins on June 14 in Moscow as Russia take on Saudi Arabia.
— Channel 4 News (@Channel4News) March 14, 2018
"To those who seek to do us harm, my message is simple: you are not welcome here."
Theresa May says 23 Russian diplomats will be expelled after the nerve agent attack on a former spy in Salisbury, alongside a crackdown on "serious criminals and corrupt elites". pic.twitter.com/IZ6UEA6gyJ
Speaking in the Commons, Labour's Luciana Berger asked: "Further to the confirmation that no minister or member of the Royal Family will be attending the World Cup this summer, does she believe this should also extend to senior FA officials, and will she ask our Nato and EU allies to join us in this endeavour?"
Mrs May replied: "I think the attendance at sporting events is a matter for the sporting authorities, it's a matter for them.
"They will be aware of the statement I have made today, they will be aware that we're saying no ministers or members of the Royal Family will be attending the World Cup and I'm sure they will want to be considering their position."
Ms May has signalled approval for MI5 to review Putin's influence over "universities, think tanks, financial institutions and political parties" in the UK.
She told MPs that she would "look at" tasking the security services to review Russia's influence, after giving an update in the Commons on the Salisbury incident.
Senior Labour figure Ben Bradshaw made the suggestion after welcoming her approach to Russia, which drew cheers from the Tory benches.
He said: "Will she task the intelligence and security services to investigate Putin's influencing operations in our universities, in our think tanks, in our financial institutions and in our political parties?"
Mrs May said: "He raises an important issue about the propaganda activities that are being undertaken by the Russian state and I will certainly look at the suggestions he has made."
A number of MPs from across the house as well as the Scottish and Welsh First Ministers have given their support for Mrs May's measures against Russia after her statement.
Scottish First Minister Nicola Sturgeon said: "Russia's actions cannot be tolerated."
She said a "proportionate but firm response" was right and backed the Prime Minister's initial actions.
"Russia cannot unlawfully kill/attempt to kill on our streets with impunity," she said.
Welsh First Minister Carwyn Jones backed Theresa May's actions.
"Appalling acts like these cannot be tolerated," he said. "A robust and proportionate response is the right call."
"Either this was a direct act by the Russian state against our country, or conceivably the Russian government could have lost control of a military grade nerve agent" - @Theresa_May on #Salisbury pic.twitter.com/57nZbjTK4q— Sky News (@SkyNews) March 14, 2018
Earlier: UK to expel 23 Russian diplomats, British royal family not to attend the World Cup
The UK is to expel 23 Russian diplomats in retaliation for the nerve gas attack in Salisbury, Theresa May has told British MPs.
The British Prime Minister said the diplomats being expelled had been identified as “undeclared intelligence officers” and had been given a week to leave.
In her oral statement to the House of Commons, Mrs May told MPs that Russia had responded to her demand for an explanation of events in Salisbury with "sarcasm, contempt and defiance".
Mrs May said: "Their response has demonstrated complete disdain for the gravity of these events."
Russia had failed to provide any "credible" explanation of events and of why it has "an undeclared chemical weapons programme in contravention of international law", she said.
She said that the UK was suspending high-level contacts with Russia and that dignitaries, including members of the UK's royal family, will not attend this summer’s World Cup.
She announced the suspension of “all planned high-level bilateral contacts between the United Kingdom and the Russian Federation”.
This includes the revocation of an invitation for foreign minister Sergei Lavrov to visit the UK, said Mrs May.
Mrs May said the British Government would "urgently develop proposals" for new legislative powers to "harden our defences against all forms of hostile state activity".
She said: "This will include the addition of a targeted power to detain those suspected of hostile state activity at the UK border.
"This power is currently only permitted in relation to those suspected of terrorism."
The PM has also asked the UK Home Secretary Amber Rudd to consider whether there is a need for new counter-espionage powers to "clamp down on the full spectrum of hostile activities of foreign agents in our country".
The Prime Minister said the Salisbury incident was an "unlawful use of force by the Russian state against the UK".
Theresa May told MPs the National Security Council had agreed "immediate actions to dismantle the Russian espionage network in the UK".
There would be "urgent work to develop new powers to tackle all forms of hostile state activity and to ensure that those seeking to carry out such activity cannot enter the UK".
Russian ambassador to the UK Alexander Yakovenko told Sky News the UK’s response to the Salisbury incident is “unacceptable” and a “provocation”.
Mr Yakovenko told Sky News after his Foreign Office meeting: "I said everything what is done today by the British Government is absolutely unacceptable and we consider this a provocation."
He said the UK should "follow international law" and under the rules of the Organisation for the Prohibition of Chemical Weapons "they have to present a request to the organisation and then we are happy to consider this within 10 days".
The UK's actions were "nothing to do with the situation that we have in Salisbury, we believe this is very serious provocation".
12.39pm: UK summons Russian ambassador to brief him on measures after Sergei Skripal nerve agent attack
The UK's Foreign Office said: "The UK has called for an urgent meeting of the UN Security Council to update Council members on the investigation into the nerve agent attack in Salisbury."
Russia's ambassador Alexander Yakovenko has been summoned to the Foreign Office to be updated on measures to be announced by British Prime Minister Theresa May.
Mr Yakovenko was in a meeting with a senior Foreign Office official immediately before the PM's statement to the House of Commons.
Britain's Foreign Secretary Boris Johnson was in the House to hear the PM's statement.
Nato said the UK had briefed its North Atlantic Council today about the Skripal attack.
A statement said: "Allies expressed deep concern at the first offensive use of a nerve agent on Alliance territory since NATO's foundation.
"Allies expressed solidarity with the UK, offered their support in the conduct of the ongoing investigation, and called on Russia to address the UK's questions including providing full and complete disclosure of the Novichok programme to the Organisation for the Prohibition of Chemical Weapons.
"Allies agreed that the attack was a clear breach of international norms and agreements.
"Nato regards any use of chemical weapons as a threat to international peace and security."
11.45am: Russia accuses UK of 'grossly misleading' world as EC president expresses 'full solidarity' with Theresa May
Russian foreign minister Sergei Lavrov has accused the UK of trying to "grossly mislead" the world community over the Skripal case.
According to Russian news agency Tass, Mr Lavrov told a press conference that Britain was acting as if suspicion should be regarded as "the queen of evidence".
Mr Lavrov said Moscow had not yet received an official request from the UK under the Convention on the Prohibition of Chemical Weapons, and would be prepared to respond within 10 days to an approach of this kind.
Downing Street has confirmed that Theresa May will make an oral statement to the House of Commons on the Skripal case following Prime Minister's Questions.
European Council president Donald Tusk said he would put the poisoning on the agenda of next week's European Council meeting.
He tweeted: "I express my full solidarity with PM @theresa_may in the face of the brutal attack inspired, most likely, by Moscow. I'm ready to put the issue on next week's #EUCO agenda.
"For real friends, this should be obvious: At a time of fake news spreading, meddling in our elections, and attacks on people on our soil with nerve agent, the response must not be transatlantic bickering but transatlantic unity."
For real friends, this should be obvious: At a time of fake news spreading, meddling in our elections, and attacks on people on our soil with nerve agent, the response must not be transatlantic bickering but transatlantic unity.— Donald Tusk (@eucopresident) March 14, 2018
10.09am: Theresa May chairs national security council as Russia says it 'won't accept the language of ultimatum'
Theresa May is chairing a meeting of the UK's national security council after the midnight deadline she set Moscow over the spy poisoning case passed.
Russia said yesterday it would ignore demands for an explanation over how a nerve agent was deployed in Salisbury unless Britain agreed to send it samples of the poison.
The Federation's embassy in the UK fired off a salvo of tweets warning the threat of sanctions would "meet with a response".
1/7 UK Ambassador Laurence Bristow was summoned to @MFA_Russia, where First Deputy FM Vladimir Titov strongly protested the evidence-free accusations by the UK authorities of Russia’s alleged involvement in the poisoning of Sergei Skripal and his daughter Yulia. pic.twitter.com/wQvl2AwLJI— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
President Vladimir Putin's spokesman Dmitry Peskov told reporters in Moscow that Russia had "no connection" to the Skripal poisoning and "won't accept the language of ultimatum" from the UK.
According to Russian news agency Tass, Mr Peskov said: "Moscow's stance is well-known, London was told about Moscow's position through diplomatic channels. Moscow has no connection to the incident that took place in the United Kingdom.
"Moscow won't accept absolutely unfounded accusations against it, which are not substantiated by any evidence, and won't accept the language of ultimatum."
Mr Peskov said Russia was "open for co-operation" in investigating the incident, but had not received any "mutual readiness" from the UK.
"We hope that common sense will prevail and that other countries will at least stop to think if there is any proof or there is none, and if reproaches against Moscow have grounds to rely on," he said.
"Common sense prompts and demonstrates that no grounds for charges can exist."
Counter-terrorism police in the UK, meanwhile, launched an investigation into the death of a Russian exile who was a close friend of Vladimir Putin critic Boris Berezovsky.
2/7 It was stated that the actions of the UK authorities are a clear provocation and that the Russian Federation was not involved in the incident that took place in Salisbury on 4 March, 2018. pic.twitter.com/WppmgfgO6L— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
Scotland Yard said a man in his 60s was found at a home in Clarence Avenue, New Malden, south-west London on Monday and that the cause of his death is unexplained - but there was "no evidence to suggest a link to the incident in Salisbury".
Mrs May has warned she will set out a "full range" of measures to be taken in response if there is no credible response from the Kremlin about the attack on Sergei Skripal and his daughter Yulia.
She is chairing a meeting this morning of senior intelligence officials and ministers to discuss developments in the case.
3/7 Moscow will not respond to London’s ultimatum until it receives samples of the chemical substance to which the UK investigators are referring. pic.twitter.com/B5CNtimcc3— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
The British premier is likely to make a statement in the House of Commons to update MPs after Prime Minister's Questions.
Britain's options are being weighed up by the Government - with a cyber counter-strike said to be among the possible measures being considered, along with economic, financial and diplomatic action.
In a series of tweets, the Russian Embassy said: "Moscow will not respond to London's ultimatum until it receives samples of the chemical substance to which the UK investigators are referring."
4/7 Britain must comply with the Chemical Weapons Convention which stipulates joint investigation into the incident, for which Moscow is ready. pic.twitter.com/8TxEBOpBQ8— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
"The incident appears to be yet another crooked attempt by the UK authorities to discredit Russia," it added.
The embassy said those calling for the expulsion of Russian diplomats "don't care about Global Britain and its diplomats in Moscow".
World leaders, including Donald Trump and Angela Merkel, voiced their support for the UK as the deadline approached.
5/7 Without that, there can be no sense in any statements from London. The incident appears to be yet another crooked attempt by the UK authorities to discredit Russia. pic.twitter.com/VLk6UCePVj— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
Mrs May said on Monday her Government had concluded it is "highly likely" Russia was responsible for the attack which left ex-spy Mr Skripal and his daughter in a critical condition in hospital.
She demanded that Moscow account for how a Russian-produced nerve agent could have been deployed in Salisbury and vowed to set out measures Britain would adopt if no credible response was received by the end of Tuesday.
6/7 Any threat to take “punitive” measures against Russia will meet with a response. The British side should be aware of that. pic.twitter.com/DFAaB5orQE— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
President Trump told Mrs May in a phone call the US is "with the UK all the way" and German Chancellor Angela Merkel said she stood in "full solidarity" with Britain, according to Downing Street.
Police said investigations could take several weeks as they carry out a "painstaking" operation to identify how the Novichok nerve agent was used to poison Mr Skripal on British soil.
The former double agent, 66, and his daughter, 33, were found slumped on a bench in Salisbury, Wiltshire, on March 4.
7/7 Today the Embassy sent a note to @ForeignOffice reiterating that Russia is not involved in the Salisbury incident and outlining the above mentioned demands for joint investigation pic.twitter.com/Vj5mxFBpfA— Russian Embassy, UK (@RussianEmbassy) March 13, 2018
Police in the UK and MI5 are to look into allegations that a string of other deaths on UK soil may be linked to Russia.
- Digital Desk and PA