Iran vowed on Saturday not to let an attack on one of its oil tankers off the coast of Saudi Arabia in the Red Sea to go unanswered.
Ali Shamkhani, the secretary of the Supreme National Security Council, said clues had been uncovered as to who was behind what he called a "missile attack" on the Sabiti tanker.
"Maritime piracy and wickedness in international waterways... will not be left unanswered," he said.
“A special committee has been set up to investigate the attack on Sabiti... with two missiles and its report will soon be submitted to the authorities for decision,” Shamkhani said.
"By reviewing the available video and gathered intelligence evidence, the primary clues to the dangerous adventure of attacking the Iranian oil tanker in the Red Sea have been uncovered," he added.
Shamkhani warned of "disturbing risks" for the global economy as a result of insecurity in international waterways.
The National Iranian Tanker Company, which owns the Sabiti, said its hull was hit by two separate explosions on Friday off the Saudi port of Jeddah. But the state-owned company denied reports the attack had originated from Saudi soil.
The attack caused oil to spill from the tanker into the Red Sea, the NITC said, before it was eventually controlled and the vessel began slowly moving back toward Persian Gulf waters.
NITC chief Nasrollah Sardashti said the crew were safe and the vessel would reach Iranian waters within 10 days.
There was no claim of responsibility for the incident.
The US Navy’s Fifth Fleet, which operates in the region, said it was aware of the reports but had no further information.
Saudi Arabia said it received a distress message from the damaged tanker but the vessel kept moving and switched off its transponder before it could provide assistance, the state news agency SPA reported on Saturday.
According to the latest data from shipping monitors Marine Traffic, the Sabiti was still in the Red Sea about 400 kilometers (250 miles) south of Jeddah.
Oil prices rose on the news of the incident and industry sources said it could drive up already high shipping costs.
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 toward 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.
The incident comes after a spate of still unexplained attacks on shipping in and around the vital seaway to the Persian Gulf as well as drone and missile attacks on Saudi oil installations.
Washington accused Tehran of attacking the vessels with mines and to be behind the drone assault, something it strongly denied.
In a statement, Iran's government spokesman Ali Rabiei called Friday's attack "cowardly" and said Tehran would give a "proportionate response" following investigations “but we will wait until all aspects of the plot are clarified”.
"The question now is, those who accused Iran of disrupting free maritime transport in the Persian Gulf and the attack on Aramco installations with no proof, are they ready to once again defend the principles of free maritime transportation in international waters and condemn such an attack on an Iranian ship?" he said.
“Iran is avoiding haste, carefully examining what has happened and probing facts,” Rabiei said.
AFP and Reuters contributed to this story.