Obama: US has offered no 'freebies' to Iran

April 15: President Obama waves as he arrives at the Convention Center for the second working session of the sixth Summit of the Americas in Cartagena, Colombia. (AP)

CARTAGENA, Colombia – Exposing a rift with Israel, President 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. would welcome the communist-run island's transition to democracy. There could be an opportunity for such a shift to take place in the coming years, Obama said.

Standing alongside Colombian President Juan Manuel Santos, Obama also proclaimed a free trade agreement between their countries as a "win-win." Obama announced that the trade pact can be fully enforced next month, now that Colombia has enacted a series of protections for workers and labor unions.

As Obama was meeting with Latin American leaders in Colombia this weekend, negotiators from the U.S. and five other world powers were in Turkey for a fresh round of nuclear talks with Iran.

While previous talks have done little to dissuade Iran from moving forward on its nuclear program, diplomats called the latest negotiations constructive and useful. Both sides agreed to hold more talks in Baghdad at the end of May.

The Israeli prime minister balked at the announcement of more talks, saying the intervening five weeks would simply give Iran more time to continue enriching uranium without restrictions. Netanyahu has said Iran uses diplomatic negotiations as a diversion while it continues to pursue a nuclear weapon.

Israel has raised the prospect of a preemptive military strike on Iran's nuclear facilities. The Obama administration has urgently sought to hold off Israeli military action, which would likely result in the U.S. being pulled into a conflict as well. The U.S. believes a combination of diplomacy and crippling economic sanctions could push Iran to abandon its nuclear ambitions.

Obama reaffirmed his commitment to that approach Sunday, saying it was "absolutely the right thing to do."

Iran insists its nuclear program is for peaceful purposes and says it does not seek a bomb.