This Iranian-owned oil tanker was struck by missiles, according to Iranian media.
Now - a day after the incident - Iran has responded, with a government spokesman on Saturday calling it a "cowardly attack."
Quoted by official news agency IRNA, the spokesman also said Iran would respond after the facts had been looked at.
According to Iranian media, the tanker Sabiti was hit in Red Sea waters off Saudi Arabia on Friday. There's been no claim of responsibility and it has yet to be independently confirmed.
It's the latest incident involving oil tankers in the Red Sea and Gulf region, and may ratchet up tensions between Iran and Saudi Arabia.
The United States has blamed Iran for attacks on tankers in the Gulf in May and June as well as for strikes on Saudi oil sites in September.
Tehran has denied having a role in any of them.
But in an attempt to cool things off, the Iranian Foreign Ministry on Saturday said that Tehran is prepared to hold talks with Saudi Ariabia... with or without a mediator.