President Barack Obama took on critics of a newly brokered nuclear deal with Iran on Monday by saying their tough talk was good for politics but not for U.S. security.

Top Republicans - as well as US ally Israel - have criticized Obama for agreeing to the deal and some Democrats, who tend to more hawkish about Iran than Obama's administration, have been sceptical about it.

A number of lawmakers, especially Republicans, insisted they would try to enact stiffer new sanctions despite the deal, which the United States and its partners say may ultimately prevent Tehran from obtaining a nuclear bomb.

Obama, who has long been upbraided for his desire to engage with U.S. foes, took heat as a presidential candidate in 2008 for saying he would talk to Iran, which has not had diplomatic relations with Washington for more than three decades.

On Monday, however, he alluded to those foreign policy goals during remarks that were otherwise focused on immigration reform. He said he had ended the war in Iraq and would end the war in Afghanistan next year, two things he pledged to do as a candidate.

"When I first ran for president I said it was time for a new era of American leadership in the world, one that turned the page on a decade of war and began a new era of our engagement with the world," he said during a visit to San Francisco.

"As president and as commander in chief, I've done what I said."

Though the agreement forged by six major powers and Iran over the weekend is a first step, aimed at buying time to negotiate a comprehensive deal, the White House sees it as a form of vindication for policies that Obama has long espoused.

Under the interim deal, Iran will accept restrictions on its nuclear program in exchange for limited relief from economic sanctions that have gradually crippled its economy and slashed its oil exports.

It was widely praised in Iran and the region.

Israel, however, has argued that a partial deal is a bad deal and that easing sanctions, even temporarily, decreases the leverage that the United States and others have over Iran.

Obama said that if Tehran follows through on its part of the pact, it would chip away at years of mistrust between the two countries. To his critics, Obama was especially direct.

"Huge challenges remain, but we cannot close the door on diplomacy, and we cannot rule out peaceful solutions to the world's problems. We cannot commit ourselves to an endless cycle of conflict," he said.

"Tough talk and bluster may be the easy thing to do politically, but it's not the right thing for our security."

SKEPTICISM IN CONGRESS

Obama is in the middle of a three-day western swing to raise money for the Democratic Party while promoting his policy priorities on the economy. The Iran deal could be exploited politically by Republicans to garner money, and votes, from Israel supporters who view it as a threat to the Jewish state.

Pro-Israel lobbyists had been pushing American lawmakers hard to keep to a tough line on Tehran. The American Israel Public Affairs Committee issued a memo to supporters on Monday raising doubts about many terms of the interim agreement, including that it allows Iran to continue uranium enrichment.

But the pro-Israel advocacy group did not call for new sanctions to be imposed right away. AIPAC said it supported legislation that would allow sanctions to take effect if Iran violates the interim pact or a comprehensive deal falls through.

The White House - and the Iranian government - have said Congress could kill the deal if it enacts new sanctions now.

U.S. Senate Majority Leader Harry Reid, a Democrat, said on Monday the Senate will consider legislation next month to impose tighter sanctions on Iran, but only after studying the issue and possibly holding hearings.

"They will study this, they will hold hearings if necessary, and if we need work on this, if we need stronger sanctions, I am sure we will do that," Reid said on National Public Radio.

Comments from Reid and other lawmakers bolstered expectations that the Senate would likely hold off on imposing new sanctions for the next six months as negotiations continue.

Obama, at a fundraiser later in Los Angeles, said all options remained on the table for dealing with Iran. But he noted poignantly that his frequent visits to the Walter Reed military medical center where wounded service men and women are treated had influenced his push for diplomacy.

"I spend too much time at Walter Reed looking at kids - 22, 23, 24, 25 years old - who've paid the kind of price that very few of us in this room can imagine on behalf of our freedom, not to say that I'm going to do every single thing that I can to try to resolve these issues without resorting to military conflict," he said.

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