GENEVA (AP) -- A new round of talks on Iran's nuclear program has begun in Geneva.
Both Tehran and the six world powers indicate a first-step agreement is possible that would roll back Iran's nuclear program in exchange for limited sanctions relief.
But there was tough talk from both sides. Iran's supreme leader, Ayatollah Ali Khamenei insists there are limits to the concessions Tehran will make. He also blasted Israel as "the rabid dog of the region" - comments that French President Francois Hollande calls "unacceptable."
Israel remains firmly opposed to any deal, and there's uneasiness both in the U.S. Congress and among Iranian hard-liners.
Vice President Joe Biden has been pressing senators to hold off on more sanctions against Tehran. The White House says Biden told a dozen Democratic senators Wednesday that existing sanctions have been tough enough to force Iran to the negotiating table.