'No need' for new Iran sanctions: Obama

US President Barack Obama has said there is no need to impose new sanctions on Iran because current negotiations have a good chance to halt the country's controversial nuclear programme which has been a challenge to America's security for over a decade.

"There is no need for new sanctions legislation, not yet," Obama told a White House news conference yesterday.

Obama said that Iran has agreed to actions that will let other nations determine whether it is trying to weaponise nuclear materials. The president said he would support tougher sanctions later if Iran violates the agreement.

"On Iran, there is the possibility of a resolution to a problem that has been a challenge for American national security for over a decade now, and that is getting Iran to, in a verifiable fashion, not pursue a nuclear weapon," Obama said.

He asked the Congress not to impose new sanctions against Iran and give current diplomacy a chance to work.

"Even with the interim deal that we struck in Geneva, we had the first halt and, in some cases, some rollback of Iran's nuclear capabilities-- the first time that we've seen that in almost a decade," he said, referring to the recent deal with Iran by the US-led group of six countries.

"We now have a structure in which we can have a very serious conversation to see is it possible for Iran to get right with the international community in a verifiable fashion to give us all confidence that any peaceful nuclear program that they have is not going to be weaponised in a way that threatens us or allies in the region, including Israel," Obama said.

His comments came a day after White House press secretary Jay Carney warned for the first time that Obama would veto any new sanctions legislation Congress enacts before the interim deal with Iran expires.

Obama said keeping aside the current prospect for a diplomatic resolution would increase the chances of a military conflict over the issue and warned lawmakers that the war-weary American public is in no mood for that.

"Now, I've been very clear from the start, I mean what I say: It is my goal to prevent Iran from obtaining a nuclear weapon. But I sure would rather do it diplomatically," he said.