Iran seized a Marshall Islands-flagged oil tanker in the Gulf of Oman in international waters on Thursday, the U.S. Navy said, the latest in a series of seizures and attacks on commercial vessels in Gulf waters since 2019.

Iran’s state television IRIB News reported on its Telegram channel that the Iranian navy had seized a Marshall Islands-flagged ship, but gave no further details.

The U.S. Navy identified the vessel as the Advantage Sweet which, according to Refinitiv ship tracking data, is a Suezmax crude tanker which had been chartered by oil major Chevron and had last docked in Kuwait.

Its manager is listed as Genel Denizcilik Nakliyati AS, a Turkey-based company which did not immediately respond to a request for comment.

“Iran’s continued harassment of vessels and interference with navigational rights in regional waters are a threat to maritime security and the global economy,” the U.S. Navy said, adding that Iran has in the past two years unlawfully seized at least five commercial vessels in the Middle East.

Iranian authorities did not immediately respond to a Reuters request for comment.

Since 2019 there have been a series of attacks on shipping in the strategic Gulf waters at times of tension between the United States and Iran.

Iran last November released two Greek-flagged tankers it had seized in the Gulf in May in response to the confiscation of oil by the United States from an Iranian-flagged tanker off the Greek coast.

Almost a fifth of the world’s oil passes through the Strait of Hormuz, a narrow chokepoint between Iran and Oman which the Advantage Sweet had passed through, according to ship tracking data.

Indirect talks between Tehran and Washington to revive Iran’s 2015 nuclear pact with world powers have stalled since September over a range of issues, including the Islamic Republic’s violent crackdown on popular protests, Tehran’s sale of drones to Russia and acceleration of its nuclear program.

The U.S. Navy, whose Fifth Fleet is based in the Gulf island state of Bahrain, called on Iran’s Islamic Revolutionary Guards Corps Navy (IRGCN) to immediately release the tanker.

The ship issued a distress call during the seizure, the U.S. Navy statement said.

Maritime security company Ambrey said the tanker was boarded via helicopter and seized by the IRGCN off the coast of Bandar-e Jask in Iran.

According to the International Maritime Organisation shipping database, the Advantage Sweet is owned by a China-registered company called SPDBFL No One Hundred & Eighty-Seven (Tianjin) Ship Leasing Co Ltd.

Iran army says seized oil tanker collided with Iranian vessel

Iran’s army said on Thursday it had seized a Marshall Islands-flagged oil tanker in the Gulf of Oman after it collided with an Iranian boat, injuring several crewmen, Iranian state media reported.

“A Marshall Islands-flagged oil tanker was seized by Iranian army’s naval force in the Persian Gulf after it collided with an Iranian boat in the Gulf of Oman and tried to flee,” the army statement said.

“Two members of the boat’s crew are missing and several were injured due the collision of the ship with the boat.”