CARTAGENA, Colombia -- Exposing a rift with Israel, President Barack Obama on Sunday insisted that the United States has 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 time for diplomacy.
His assessment, delivered at the close of a Latin American summit in Colombia, came after Israeli Prime Minister Benjamin Netanyahu on Sunday had said the U.S. and world powers gave Tehran a "freebie" by agreeing to hold more talks next month.
Obama shot back: "The notion that somehow we've given something away or a 'freebie' would indicate Iran has gotten something. In fact, they've got some of the toughest sanctions that they're going to be facing coming up in just a few months if they don't take advantage of these talks."
Still, in a news conference here, Obama warned to Iran, "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 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 all-around, even as labor leaders back home denounced it. 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.
Obama had hoped to keep his role in the Summit of the Americas focused on the economy and the prospect of the region's rapid economic rise as a growth opportunity for American businesses.
But that message was quickly overshadowed by an alleged prostitution scandal involving Secret Service personnel who were in Colombia to set up security for Obama's trip. The president said Sunday that he expected a full, rigorous investigation of the allegations, and said he would be angry if the accusations turn out to be true.
As Obama met with Latin American leaders, 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 probably 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.
With his re-election campaign in full swing, Obama came to Colombia seeking to pitch an economic message that would appeal to voters back home. Implementation of the Colombian trade pact was a central part of that effort, and won Obama praise Sunday from the U.S. business community, which contends the pact will be an economic boon for American businesses.
Labor union officials, however, said they were disappointed by the agreement, insisting that Colombia still has an abysmal record on union rights. Union workers are a core Obama constituency, but have opposed some of his efforts to expand free-trade deals, which they believe take jobs away from U.S. companies.
Obama officials insisted they moved ahead only after Colombia took steps to halt deadly violence against labor unionists.
AFL-CIO President Richard Trumka said the announcement was "deeply disappointing and troubling" and accused the administration of placing "commercial interests above the interests of workers and their trade unions." Dan Kovalik, a lawyer with the United Steelworkers, said the announcement was "premature in light of the continued violence against unionists and human rights defenders in Colombia."
Under the terms of the trade pact, more than 80 percent of industrial and manufactured products exported from the U.S. and Colombia will immediately become duty-free, making it cheaper for American businesses to sell their goods to the South American country.
The hemispheric summit wrapped up Sunday with few notable achievements. And much of the attention was on who wasn't there -- namely, Cuba.
Some Central and South American leaders hoped to include language in the summit's final declaration stipulating that Cuba be included in the next gathering. But with the U.S. staunchly opposed to that effort, leaders decided to end their meetings without a final communique.
The U.S. insists that Cuba should not be allowed to attend the regional meetings until it enacts democratic reforms. Obama suggested Sunday that scenario may not be all that far away.
"There may be an opportunity in the coming years as Cuba begins to look at where it needs to go in order to give its people the kind of prosperity and opportunity that it needs, that it starts loosening up some constraints within that country, and that's something that we will welcome," he said.
Before departing, Obama had his only real encounter with the people of Cartagena, joining Santos in a celebration of the country's efforts to recognize Afro-Colombian communities that have been historically marginalized. The ceremony gave these communities, descendants of slaves, formal title to their land, and it prompted Obama to reflect on his own ancestry and his 2009 trip to Ghana with his family.