The U.S. and Iran are poised to hold further nuclear talks in the Swiss city of Geneva on Thursday, amid persistent fears about the prospect of military action in the oil-rich Middle East.

The upcoming round of negotiations over the future of Tehran’s nuclear program come as the U.S. continues to build up military forces in the region and as President Donald Trump warns of “bad things” if Iran doesn’t agree to a nuclear deal.

The U.S. president on Tuesday spoke briefly about Iran during his nearly two-hour State of the Union address but primarily focused on domestic policy and other political issues.

“We are in negotiations with them. They want to make a deal, but we haven’t heard those secret words: ‘We will never have a nuclear weapon,’” Trump said.

“My preference is to solve this problem through diplomacy. But one thing is certain, I will never allow the world’s number one sponsor of terror, which they are by far, to have a nuclear weapon.”