European and Iranian diplomats will meet in Geneva on Tuesday to try to restart negotiations on limiting Iran’s nuclear enrichment program and avoid triggering painful sanctions on Iran that were suspended under a landmark 2015 deal.

That deal expires on Oct. 18. Its European signatories have said they will reinstate the sanctions unless there is significant progress on negotiating a new agreement. Time is running out for them to decide, and last month the Europeans offered to extend the deadline.

In return, they have demanded that Iran do three things: restart talks in earnest on the status of its uranium stockpile and nuclear program, account for its 400 kilograms of near weapons-grade uranium and restore access to inspectors from the U.N. nuclear watchdog, the International Atomic Energy Agency. The agency is charged with monitoring the Nuclear Nonproliferation Treaty, which Iran has signed, and with separately tracking Iran’s compliance with the 2015 nuclear deal.

The United States had also been part of the 2015 agreement, but President Trump withdrew from it in 2018. More recently, Iran halted fledgling talks with the United States after Israel launched a 12-day war in June that damaged Iran’s nuclear facilities and other infrastructure. Following that conflict, which included a U.S. bombing campaign intended to destroy Iran’s nuclear-enrichment capability, Iran rejected direct talks with Washington on a new nuclear deal.

Britain, France and Germany have urged Iran to meet again with the United States and to make a concrete step toward restoring international trust in its declarations about its nuclear activities. Iran has insisted that its program is for civilian use only, despite its enriching enough uranium to near weapons-grade, which is needed to make 10 nuclear warheads.