On Thursday, Iran’s Revolutionary Guards forcibly seized a commercial ship in international waters in the Gulf and the vessel was possibly involved in smuggling, a US Navy spokesperson said.

US 5th Fleet spokesperson Commander Tim Hawkins said the US Navy had monitored the situation and decided not to make any further response.

British maritime security company Ambrey said it was aware of an attempted seizure by Iranian forces of a small Tanzanian-flagged tanker, around 59 nautical miles northeast of the Saudi Arabian port city of Dammam.

“Iran regularly intercepts smaller tankers it suspects of smuggling oil,” the company added in a note; as per Reuters.

About a fifth of the world’s supply of seaborne crude oil and oil products passes through the Strait of Hormuz, a chokepoint between Iran and Oman, according to data from analytics firm Vortexa.