According to a statement from Iran's Revolutionary Guard, a so-called supertanker - a particularly large oil tanker - struck a mine in the Strait of Hormuz. The statement said the ship was carrying more than two million barrels of crude oil at the time.
The Iranian claim is difficult to verify and has not been confirmed by other parties.
One or two ships were attacked in the central Persian Gulf on Friday, according to the British Navy's maritime traffic watchdog, UKMTO.
UKMTO described two attacks that occurred close to each other but at different times. It is unclear whether different ships were attacked. In one attack, the ship was reportedly hit by rocket-propelled grenades fired from a smaller boat. No one was injured.