An Iranian government spokesman has described as "cowardly" an attack on its oil tanker, which was hit in Red Sea waters off the coast of Saudi Arabia on Friday.
"Iran is avoiding haste, carefully examining what has happened and probing facts," spokesman Ali Rabei was quoted as saying by the official news agency, IRNA.
He said Iran would respond after the facts had been studied. "An appropriate response will be given to the designers of this cowardly attack, but we will wait until all aspects of the plot are clarified," he said.
Iranian media said the incident could stoke friction in a region rattled by attacks on tankers and oil installations since May.
The National Iranian Tanker Company (NITC), which owns the Sabiti, said its hull was hit by two separate explosions off the Saudi port of Jeddah.
But the state-owned company denied reports the attack had originated from Saudi soil.
For its part, Saudi Arabia said it received a distress message on the same day from a damaged Iranian tanker in the Red Sea but the vessel kept moving and switched off its transponder before it could assist, state news agency SPA reported on Saturday.
SPA said the Sabiti tanker did not respond to many communications from the Saudi authorities.
A senior Iranian security official said video evidence had provided leads about the incident, the semi-official news agency, Fars, reported.
"Piracy and mischief on international waterways aimed at making commercial shipping insecure will not go unanswered," said Ali Shamkhani, secretary of Iran's top security body, according to Fars.
Leakage of cargo from the tanker has been stopped as it heads for the Gulf, the semi-official Iranian news agency Mehr reported.
"The tanker is heading for Persian Gulf waters and we hope it will enter Iranian waters safely," Mehr quoted an unnamed official as saying. "The cargo leakage has stopped."
Iran's foreign ministry said the ship was hit twice, without saying what struck it. State television broadcast images from the Sabiti's deck, saying they were taken after the attack but showing no visible damage. The ship's hull was not in view.
The incident, yet to be independently confirmed, is the latest involving oil tankers in the Red Sea and Gulf region, and may ratchet up tensions between Iran and Saudi Arabia, long-time regional adversaries fighting a proxy war in Yemen, which lies at the southern end of the Red Sea.
The United States, embroiled in a dispute with Iran over its nuclear plans, has blamed Iran for attacks on tankers in the Gulf in May and June as well as for attacks on Saudi oil sites in September. Tehran has denied having a role in any of them.
The US Navy's Fifth Fleet, which operates in the region, said it was aware of the reports but had no further information.
There was no claim of responsibility for the reported incident.
Political risk consultancy Eurasia Group said it did not have firm evidence about who may have been behind the incident.
"The proximity of the tanker at the time of the attack to Saudi Arabia's Jeddah port might imply that the missiles could possibly have been launched from the kingdom.
"Another plausible theory is that it was an Israeli sabotage operation...The purpose would be to disrupt Iranian tanker activity in the Red Sea corridor as it heads towards the Suez Canal. A third possibility would be that the attack was conducted by a terrorist group," Eurasia said in a statement.
The Red Sea is a major global shipping route for oil and other trade, linking the Indian Ocean with the Mediterranean via the Suez Canal.
Crude prices jumped briefly on the news of the alleged attack and industry sources said it could drive up already high shipping costs.
SOURCE: Al Jazeera and news agencies