ERBIL, Kurdistan Region of Iraq - US Central Command (CENTCOM) on Sunday condemned the seizure of a Marshall Islands-flagged oil tanker by Iran's Islamic Revolutionary Guard Corps (IRGC) in the Strait of Hormuz on Friday, calling it an "illegal boarding."

On Saturday, the IRGC Navy confirmed it seized the cargo of the Talara oil tanker off Iran’s southern Makran coast on Friday while it was en route to Singapore, acting on a judicial order.

"Iran's use of military forces to conduct an armed boarding and seizure of a commercial vessel in international waters constitutes a blatant violation of international law, undermining freedom of navigation and the free flow of commerce," CENTCOM said in a statement on Sunday.

The statement added that IRGC forces “steered the tanker to Iran’s territorial waters” after arriving by helicopter, and the vessel remains there.

The vessel had been carrying roughly 30,000 tons of petrochemical products and was traveling toward Singapore.

Additional reporting showed that a US Navy MQ-4C Triton surveillance drone had been circling above the area for several hours as the seizure unfolded, according to flight-tracking data analyzed by the Associated Press.

The United Kingdom Maritime Trade Operations center also acknowledged the incident, saying a possible “state activity” caused the Talara to alter course and move into Iranian territorial waters.

Columbia Shipmanagement, the Cyprus-based company responsible for the vessel, later said it had lost contact with the tanker, which was transporting high-sulfur gasoil.

Iranian state media said the seizure was carried out as part of the IRGC’s mandate to protect the country’s economic interests.

Iran has previously warned that it could block the Strait of Hormuz in response to international sanctions. 

The waterway is one of the world’s most important shipping routes and its most vital oil transit chokepoint.

In October, Iran’s top IRGC naval commander warned that Tehran could act to restrict oil shipments through the strait following new US sanctions targeting its energy exports, saying it will defend the country’s interests in the Persian Gulf and the Sea of Oman.