Iran seized a tanker with Iraqi crude destined for Turkey on Thursday in retaliation for the confiscation last year of the same vessel and its oil by the United States, Iranian state media reported.

The seizure of the Marshall Islands-flagged St Nikolas coincides with weeks of attacks by Yemen's Iran-backed Houthi militias targeting Red Sea shipping routes.

"After the theft of Iranian oil by the United States last year, St Nikolas tanker was seized by Iran's Navy this morning with a judicial order ... it is en route to Iranian ports," the semi-official Fars news agency reported, citing a statement by the Navy.

The St Nikolas, was seized by the United States last year in a sanctions enforcement operation when it sailed under a different name, Suez Rajan. Following the move, Iran warned the US that it would "not go unanswered".

The St Nikolas was boarded by armed intruders as it sailed close to the Omani city of Sohar, according to British maritime security firm Ambrey, and its AIS tracking system was turned off as it headed in the direction of the Iranian port of Bandar-e-Jask.

"Communication with the oil tanker, St Nikolas, under Marshall Islands flag and owned by the Greek shipowner Empire Navigation has been cut off around 06:30 on Jan. 11 in the waters of Oman," Turkish oil refiner Tupras said in an emailed statement, confirming it had bought the cargo from Iraqi state marketer SOMO.

"The incident has no impact on our refinery operations," the Turkish firm - which operates the 241,500 barrel per day (bpd) capacity Izmir refinery in Aliaga - added.

The ship loaded around 145,000 metric tonnes of oil in the Iraqi port of Basra and was heading to Aliaga in western Turkey via the Suez Canal, Empire Navigation said, adding that it had lost contact with the vessel.

The vessel is manned by a crew of 19 including 18 Filipino nationals and one Greek national, Empire Navigation said.

While Yemen's Houthis have since October attacked commercial vessels in the Red Sea to show support for Palestinian militant group Hamas in its fight against Israel, those incidents have been concentrated on the Bab al-Mandab Strait, to the southwest of the Arabian Peninsula.

Thursday's incident is located closer to the Strait of Hormuz, between Oman and Iran. (Reuters)