The Iranian Navy has reportedly seized a US ship with 34 crew members on board, for violating Iran’s waters in the Persian Gulf. The Pentagon denies the vessel belongs to the US, claiming it is registered in the Marshall Islands.

A Pentagon spokesman has confirmed that Iranian forces boarded the Marshall Island-flagged Maersk Tigris vessel after patrol boats fired warning shots across its bow and ordered it deeper into Iranian waters, Reuters reports.

The vessel initially ignored the warning but complied after the shots were fired, U.S. Army Colonel Steve Warren said.

The ship had no US citizens on board and was traveling through the Strait of Hormuz when it was seized, the spokesman said, adding that US planes and the USS Farragut responded to a distress call from the vessel and are monitoring the situation.

According to Reuters tracking data, the Maersk Tigris is ‘underway.’ Its status is set to ‘fast’ and its destination is listed as Jebel Ali, United Arab Emirates. The Marine Traffic tracking system also says it is heading for Jebel Ali, at a speed of 4.5 knots.