Iranian state TV on Friday broadcast clips of what it said were Iranian naval forces seizing a U.S. tanker in the Gulf of Oman.

The seizure of the St. Nikolas, earlier on Thursday, is at the center of a major dispute between Washington and Tehran, and may likely stoke regional tensions.

The tanker was carrying Iraqi crude destined for Turkey.

Vessel tracking software shows its course - the tanker turned off its AIS tracking system as it turned toward an Iranian port.

U.S. authorities seized the St. Nikolas last year in a sanctions operation, and when it had sailed under a different name, Sueze Rajan.

Tehran says its action Thursday was in retaliation for that earlier U.S. confiscation.

The seizure coincides with weeks of attacks by Yemen's Iran-backed Houthi militias targeting Red Sea shipping routes.

White House national security spokesperson John Kirby condemned Iran's actions on Thursday.

"The Iranian government should immediately release the ship and its crew. These provocative and unacceptable actions need to stop. We'll continue to work with our allies and partners to deter and confront the full range of Iran's concerning and destabilizing behavior in close coordination, of course, with the international community"

Iran seizes oil tanker in Gulf of Oman, raising Middle East tensions

The Iranian navy seized an oil tanker in the Gulf of Oman on Thursday, according to state-run media, raising tensions in the already-fraught Middle East.

The seizure was executed under a court order as the tanker had confiscated Iranian oil that was then handed over to the United States, the Public Relations Department of the Iranian Navy said, according to the state-run Islamic Republic News Agency.

The ship was being taken to Iranian southern ports, it said.

Iran identified the vessel as Suez Rajan, a tanker that was seized by the United States last year with nearly a million barrels of Iranian crude oil on board. Court documents state that Suez Rajan Limited pleaded guilty to violating U.S. sanctions for taking its shipment to China.

The Marshall Islands-flagged, Greek-owned tanker has been re-christened St. Nicholas since.

Empire Navigation, St. Nicholas' operator, confirmed in a statement that the ship with 19 crew on board was seized, saying it has not had contact with it since about 6:30 a.m. Athens' time.

The vessel was loaded days earlier in Iraq with crude oil destined for Turkey via the Suez Canal.

"We condemn this apparent seizure," National Security Council Coordinator for Strategic Communications John Kirby told reporters Wednesday during a White House press conference.

"The Iranian government should immediately release the ship and its crew. These provocative and unacceptable actions need to stop.

"We'll continue to work with our allies and partners to deter and confront the full range of Iran's concerning and destabilizing behavior in close coordination, of course, with the international community."

The seizure comes amid heightened tensions in the Middle East with war in Israel and Iran-backed Houthi militants firing on shipping vessels transiting the Red Sea. Iran-backed Hezbollah was also involved in fighting Israel over the border from Lebanon.

The United States and allies on Thursday responded to the Red Sea attacks with a large-scale retaliation against the rebels in Yemen.

And the seizure on Thursday threatens to escalate the potential of war expanding in the region.

"This unlawful seizure of a commercial vessel is just the latest behavior by Iran -- or enabled by Iran -- aimed at disrupting international commerce," U.S. State Department spokesman Matthew Miller said to reporters in a separate press conference, describing Iran's actions as "a menace to the global economy."

"We believe this kind of action will simply add uncertainty for commercial shipping and for regional and global economies," he said.

Earlier Thursday, the United Kingdom Maritime Trade Operations said four to five unknown masked men, wearing what appeared to be military outfits, boarded the St. Nicholas about 50 nautical miles east of the Oman coastal city of Sohar.

"CSO reports vessel has altered course towards Iranian territorial waters and communications with vessel have been lost," the UKMTO said in a statement. "Authorities are investigating. Vessels are advised to transit with caution and report any suspicious activity to UKMTO."

On Wednesday, the United Nations Security Council adopted a resolution, drafted by the United States and Japan, calling for Houthis to immediately stop attacking trading vessels in the Red Sea.