Secretary of State Mike Pompeo said Wednesday that the US would “soon” activate a controversial mechanism aimed at reimposing UN sanctions on Iran, despite opposition from its European allies.

The so-called “snapback” procedure, which President Donald Trump has said will be triggered this week, threatens to plunge the UN Security Council into crisis and has repercussions for the Iran nuclear deal.

“The president has made it clear we’re going to do that soon and we will,” Pompeo told reporters in Washington, declining to confirm a specific date.