Iran has promised to retaliate against the US should a cargo of crude oil be unloaded from the Suez Rajan, a suezmax currently anchored off Texas.

The tanker was seized by US authorities in April after spending more than a year anchored off Singapore amid two legal disputes and a Justice Department investigation into suspicions that its cargo was of Iranian origin.

The US Treasury Department gave the green light to offload the crude.

Islamic Revolutionary Guards Corps navy commander Alireza Tangsiri said Washington would be held response if the cargo was unloaded from the Empire Navigation-owned ship, according to a Reuters report citing Iranian state media.

Earlier this week, sources told the Wall Street Journal that saying a US government plan to auction off the 800,000 barrels on 159,000-dwt Suez Rajan (built 2011) has so far failed.

Lightering companies were said to be reluctant to handle the seized Iranian crude cargo for fear of repercussions. Today’s comments appear to confirm those fears.

“Companies with any exposure whatsoever in the Persian Gulf are literally afraid to do it,” a Houston energy executive involved in the matter told the newspaper. The executive cited worries “that the Iranians would take retribution against them”.

The April seizure of Suez Rajan was followed by Iran’s capture of the 159,000-dwt suezmax tanker Advantage Sweet (built 2012), which is on charter to Chevron.