TEHRAN, Iran (AP) — Iranian media say the Revolutionary Guard has seized an oil tanker carrying 700,000 liters of "smuggled fuel" in the Persian Gulf.

The semi-official Fars news agency says seven crew members were detained when the ship was seized late Wednesday. It did not provide further details on the vessel or the nationality of the crew.

This would mark the third commercial vessel seized by Iranian forces in recent weeks and the second accused of smuggling fuel. Tensions have soared in the Gulf in recent months as the U.S. has boosted its military presence and oil tankers have been seized by Iranian forces or targeted by unknown saboteurs.

The tensions are rooted in the U.S. decision last year to withdraw from the 2015 nuclear accord and impose sweeping sanctions on Iran.