The vessel was approached by ‌an ​unknown small vessel at ⁠0120 local time on ⁠March 5.

“The small boat approached the port ​side of the tanker and a short time ​later a loud bang was heard,” Sonangol Marine Services said in a statement.

“The crew reports that a port ​ballast tank is losing water which suggests ​some form of hull breach but the ship remains ‌stable ⁠and safely afloat.”

The vessel was not carrying cargo and there were no reports of pollution, the company added.

The tanker had a contract with ​Iraq’s state ​oil marketer ⁠SOMO and was heading to an Iraqi terminal to load 80,000 METRIC ​tons of Iraqi fuel, an Iraqi ​energy ⁠source and a shipping agent said.

Iran’s Revolutionary Guards said on ​Thursday that ⁠they had hit a U.S. tanker in the northern part of the Gulf and the vessel was on fire.

Crude tanker Sonangol Namibe reports suspected hull breach after blast near Iraq port