Iran seized a second oil tanker in less than a week, ratcheting up tensions for shipping in one of the world’s most vital trade corridors.

Iran’s Islamic Revolutionary Guard Corps Navy seized the Panama-flagged oil tanker Niovi at around 6:20 a.m. local time Wednesday as it was transiting the Strait of Hormuz, according to a statement from the US Navy. 

The incident is the latest flare up in one of the world’s most oil-rich regions. Hundreds of tankers sail through the strait each month on their way to and from ports in Saudi Arabia, the United Arab Emirates, Iraq and Kuwait.

The Niovi left Dubai and was heading for the United Arab Emirates port of Fujairah when “a dozen IRGCN fast-attack craft swarmed the vessel in the middle of the strait,” according to the US. The ship was forced to head toward Iranian territorial waters off the coast of Bandar Abbas, it said.

Iran’s Tasnim news service reported that Iranian naval forces took a foreign oil tanker in the Strait of Hormuz, without giving further details.

The vessel, built in 2005, is a supertanker capable of carrying 2 million barrels of crude, ship-tracking data compiled by Bloomberg show. It appeared to be empty earlier Wednesday, according to the latest signal from the ship’s navigation system, which includes draft data.

Global benchmark Brent crude futures stabilized after dropping as much as 2.4 percent on Wednesday, trading less than USD 75 a barrel for the first time since March.

Iran’s navy seized the Marshall Islands-flagged Advantage Sweet in international waters on April 27. The ship sailed to Bandar Abbas, where it is being held along with its crew.

Some US officials believe that move was in retaliation against a decision by the Department of Justice to force a tanker headed to China with Iranian oil to redirect to America, the Financial Times reported.