Iran has seized a Marshall Islands-flagged oil tanker in the Gulf of Oman while it was in transit in international waters, the United States Navy said on Thursday.

The Navy’s Mideast-based 5th Fleet identified the vessel as the Advantage Sweet.

“The oil tanker issued a distress call during the seizure,” the U.S. 5th Fleet tweeted, adding that it was monitoring the situation.

NAVCENT statement on Iran's unlawful seizure of a merchant vessel in the Gulf of Oman today: pic.twitter.com/EJxcsynA1m

— U.S. Naval Forces Central Command/U.S. 5th Fleet (@US5thFleet) April 27, 2023

“Iran’s actions are contrary to international law and disruptive to regional security and stability,” the 5th Fleet said in a statement. “Iran should immediately release the oil tanker.”

The vessel’s manager, a Turkish firm, did not immediately respond to a request for comment. Iran did not immediately acknowledge the seizure.