Two missiles struck the Iran-owned Sinopa oil tanker setting it ablaze off the Saudi port of Jeddah, Iranian state TV reported.
"Two missiles hit the Iran-owned ship near the Jeddah port city of Saudi Arabia," TV said, quoting the National Iranian Oil Company (NIOC).
There was no word from Saudi Arabia on the reported attack and Saudi officials did not immediately respond to requests for comment.
Iranian state television said the explosion damaged two storerooms aboard the unnamed oil tanker and caused an oil leak into the Red Sea near the Saudi port city of Jiddah.
The state-run IRNA news agency, quoting Iran's National Iranian Tanker Co., identified the stricken vessel as the Sabity. That vessel last turned on its tracking devices in August near the Iranian port city of Bandar Abbas.
Lt. Pete Pagano, a spokesman for the U.S. Navy's 5th Fleet overseeing the Mideast, said authorities there were "aware of reports of this incident," but declined to comment further.
The reported attack comes after the U.S. has alleged that in past months Iran attacked oil tankers near the Strait of Hormuz, at the mouth of the Persian Gulf, something denied by Tehran.
Friday's incident could push tensions between Iran and the U.S. even higher, more than a year after President Donald Trump unilaterally withdrew America from the nuclear deal and imposed sanctions now crushing Iran's economy.
The mysterious attacks on oil tankers near the Strait of Hormuz, Iran shooting down a U.S. military surveillance drone and other incidents across the wider Middle East followed Trump's decision.
The latest assault saw Saudi Arabia's vital oil industry come under a drone-and-cruise-missile attack, halving the kingdom's output. The U.S. has blamed Iran for the attack, something denied by Tehran. Yemen's Houthi rebels, whom the kingdom is fighting in a yearslong war, claimed that assault, though analysts say the missiles used in the attack wouldn't have the range to reach the sites from Yemen.