There are still "significant gaps" in negotiations on Iran's nuclear program, U.S. Secretary of State John Kerry said Saturday in London ahead of Sunday talks in Geneva with Iranian officials.
"There is still a distance to travel," he said, adding that if an agreement is not reached by the March 31 deadline, the talks will not be extended.
President Barack Obama "has no inclination whatsoever to extend these talks beyond the period that has been set out," said Kerry.
The Geneva meeting is aimed at helping resolve ongoing technical disputes standing in the way of an agreement between Iran and the six world powers known as the P5+1.
A deal between Iran and the group — made up of the U.S., Russia, China, Britain and France, who are permanent members of the U.N. Security Council, plus Germany — would prevent Iran from developing a nuclear weapon in exchange for easing economic sanctions. Tehran insists that its nuclear program is for peaceful purposes only.
Kerry will meet with Iranian Foreign Minister Mohammad Javad Zarif to see whether the two sides can iron out the remaining differences.
"We can make progress in these talks," he said. "A unified P5+1 has put on the table creative ideas to achieve our objective. And now we will find out whether or not Iran is able to match its words about its willingness to show that its program is fully peaceful."
Iran's Atomic Energy Organization chief, Ali Akbar Salehi, and U.S. Energy Secretary Ernest Moniz also traveled to Geneva to participate in the negotiations, their role being to help resolve the remaining technical issues.
Israel has lobbied against a U.S. deal with Iran, and some Israeli officials have accused the Obama administration of softening its demands on Tehran. Kerry told British Foreign Secretary Philip Hammond on Saturday that the P5+1 group remained united on Iran.
"Our governments remain in lockstep with our international partners on the importance of cutting off Iran's pathways to the potential of a nuclear weapon," he said.
The latest talks come as a new report from the U.N. nuclear agency says it remains concerned about the possible existence of “undisclosed nuclear-related activities” in Iran that could include work linked to the development of a nuclear payload for a missile.
But the International Atomic Energy Agency said Iran was in compliance with some provisions of a nuclear agreement.
Iranian state media reports quoted Iran's IAEA ambassador, Reza Najafi, as saying the findings showed his country’s “full transparency” and the peaceful nature of its program.