The issuing of the warrant appears to mark the first time that authorities have used the new national security law, imposed by Beijing on June 30, to target activists based outside of the city.
Chinese state broadcaster CCTV reported that the six are wanted on suspicion of inciting secession and colluding with foreign countries, but did not give any further details. In response to a CNN request for comment, a Hong Kong Police spokesperson said the "police do not comment on media reports."
US national Chu, who is the managing director of the Hong Kong Democracy Council, a Washington DC-based advocacy group promoting freedom and autonomy for Hong Kong, appears to be the first known non-Hong Kong citizen to be targeted under the new security law.
In a twitter post Friday, Chu said in ordering his arrest, China was effectively targeting a US citizen for the act of lobbying his own government. "I might be the 1st non-Chinese citizen to be targeted, but I will not be the last. If I am targeted, any American/any citizen of any nation who speaks out for HK can-and will be-too, said Chu. "We are all Hong Kongers now," he added.
According to Chu's biography, he has lived in the US as an American citizen for more than two decades. In a statement posted online, the United States China Commission, a congressional-executive body that monitors human rights and the rule of law in China, called on the Hong Kong government to repudiate the warrant and for the United Nations to begin urgent talks on the national security law and the deteriorating human rights conditions in Hong Kong.
The Hong Kong government has defended the law as necessary to protect national security, and promised that it would only affect a tiny number of people.
"The national security law is a crucial step to ending chaos and violence that has occurred over the past few months," Carrie Lam, the city's chief executive, said in July. "It's a law that has been introduced to keep Hong Kong safe. The legislation is lawful, constitutional and reasonable."
Law said that since leaving Hong Kong he has had to "sever" his relationship with his family.
"I was prepared when I left Hong Kong to be in exile; but this becoming a reality still disappoints, incapacitates, and frightens me. Indeed who can enjoy freedom from fear in the face of China's powerful political machine?" he said on social media. "What we can choose is how to respond to this fear: For me, it's with action."
Wong accused the Hong Kong government of applying the law retroactively, saying "The only reason why I was sought for 'incitement to secession and collusion with foreign forces ' must be based on my activities before the NSL is in force."
Laus, who said in a Facebook post that he is in the UK, called the arrest warrant "political persecution" and said he will "continue to express my political opinion freely." He called on the international community to "impose sanctions" on the Hong Kong and Chinese governments, including Chinese President Xi Jinping.
Journalist Vanesse Chan contributed to this report.