Iran’s president says Britain will face “repercussions” over the seizure of Iranian supertanker.

Hassan Rouhani was quoted by the official IRNA news agency Wednesday as calling the seizure “mean and wrong” during a cabinet meeting. He warns London: “You are an initiator of insecurity and you will understand its repercussions,” without elaborating.

Last week, authorities in Gibraltar intercepted an Iranian supertanker that was believed to be breaching European Union sanctions by carrying a shipment of Tehran’s crude oil to war-ravaged Syria.

The tanker’s detention comes at a particularly sensitive time as tensions between the U.S. and Iran grow over the unravelling of a 2015 nuclear deal, which President Donald Trump withdrew from last year.