Iranian state television has acknowledged that Tehran seized a South Korean-flagged oil tanker in the Strait of Hormuz.

The report on January 4 alleged that the MT Hankuk Chemi had been stopped by Iranian authorities over alleged “oil pollution” in the Persian Gulf and the strait.

The semiofficial Fars news agency said the naval forces of Iran’s Islamic Revolutionary Guard Corps (IRGC) had seized the ship.

Satellite data from MarineTraffic.com showed the MT Hankuk Chemi off the port of Bandar Abbas on January 4 without explanation. It had been traveling from Saudi Arabia to Fujairah in the United Arab Emirates.

The ship’s owners could not be immediately reached for comment.

The incident comes with tensions on the rise in the region coinciding with the anniversary of the U.S. drone strike that killed IRGC Major General Qasem Soleimani in Baghdad last year.

That attack later saw Iran retaliate by launching a ballistic-missile strike, injuring dozens of U.S. troops in Iraq. Tehran also admitted that it accidentally shot down a Ukrainian passenger jet that night, killing all 176 people on board.

As the anniversary approached, the United States has sent B-52 bombers flying over the region and sent a nuclear-powered submarine into the Persian Gulf.

Based on reporting by AFP, dpa, Reuters, and AP