"Maybe there will be a breakthrough before May 12," said Corker, chairman of the Senate Committee on Foreign Relations. May 12 is the deadline for the U.S. to recertify the deal. "If there's not, I absolutely believe that he'll leave the agreement."
The United States is hoping to reach an agreement with Britain, France and Germany to address Trump's concerns about the 2015 Iran nuclear deal. Trump has been critical of the deal negotiated under former President Barack Obama, demanding it be fixed or the U.S. will withdraw the pact and sanctions will be reinstated.
Trump has opposed terms that would allow Iran to gradually reinstate its nuclear activities and accused Iran of violating the agreement. Iran has said its nuclear program is only for peaceful purposes and its ballistic missiles solely for defense.