The United States says it is up to Iran to make the hard decisions necessary to revive the 2015 nuclear deal and ease its sanctions-ravaged economy.
"The onus is on Tehran to make decisions that it might consider difficult," State Department spokesman Ned Price said in a briefing on March 22.
Iran signed the landmark deal with the United States, Britain, France, Germany, Russia, and China in 2015. It allowed for the easing of sanctions in return for curbs on Iran’s nuclear programs.
But then-President Donald Trump pulled the United States out of the deal in May 2018, saying the terms were not strict enough to prevent Iran from developing nuclear weapons and also to punish Tehran for its putative support of extremist activity in the region.
Iran has denied it is seeking nuclear weapons, saying the program is for civilian purposes, and it has rejected accusations of support for extremists.
However, after Washington pulled out, Iran has breached limits set in the deal and has insisted that the United States lift its sanctions before it returns to the accord.
The sides have been negotiating for the past year, since U.S. President Joe Biden said he was willing to rejoin the pact as long as Iran returned to full compliance.
"There are a number of difficult issues that we are still trying to work through," he added.
"An agreement of this sort is neither imminent nor is it certain and so, that is precisely why for the better part of the year, we have been preparing for either contingency," Price said.
Price said Biden remains committed to preventing Iran from acquiring a nuclear bomb whether the deal is revived or not.