Exposing a rift with Israel, President Barack Obama on Sunday insisted that the U.S. had not "given anything away" in new talks with Iran as he defended his continued push for a diplomatic resolution to the dispute over Tehran's nuclear ambitions.

Obama said he refused to let the talks turn into a "stalling process," but believed there was still a window for diplomacy. Earlier Sunday, Israel Prime Minister Benjamin Netanyahu publicly disagreed with at least part of that strategy, saying the U.S. and world powers gave Tehran a "freebie" by agreeing to hold more talks next month.

"So far at least we haven't given away anything, other than the opportunity for us to negotiate and see if Iran comes to the table in good faith," Obama said during a news conference Sunday in Colombia, as he closed a diplomatic mission to Latin America. But Obama warned, "The clock's ticking."

Winding down his three day trip in the port city of Cartagena, Obama also sought to offer hope for fresh start with Cuba, saying the U.S.