WASHINGTON (AFP/REUTERS) - US President Barack Obama said there was "nothing new" in Benjamin Netanyahu's controversial speech to Congress on Tuesday, insisting the Israeli Prime Minister did not offer a better alternative to negotiations.

Netanyahu "did not offer any viable alternative," Obama said speaking from the Oval Office. "We don't yet have a deal. But if we are successful, this will be the best deal possible with Iran to prevent Iran from having a nuclear weapon."

Obama said he did not listen to Netanyahu's speech, but had read a transcript of it, and went on to take 11 minutes to explain why he felt the best way to keep Iran from getting a nuclear weapon was by making a deal with Teheran as soon as possible.

"We are far more likely to see it in time to do something about it," he said, waving a pointed finger vigorously. "What I'm focussed on right now is solving this problem. I'm not focussed on the politics of it. I'm not focussed on the theatre of it. My strong suggestion would be that members of Congress, as they evaluate it, stay similiary focussed."

The strong words underlined Obama's annoyance at Netanyahu using the global stage of remarks to the US Congress to address the Iran nuclear issue, and doing so just two weeks before facing an election back home in Israel where, because of election laws regarding campaigning, the speech was run on a five-minuted delay.

Urging Congress to wait to evaluate a nuclear deal with Iran until an agreement is finalised, Obama said that he would only agree to a deal that prevents Iran from obtaining a nuclear weapon.

- With additional information by Paul Zach, US correspondent