US President Barack Obama has said he does not believe Iran has the "intentions or capabilities" to attack the US and has played down the threat from Tehran.

Mr Obama said: "Any kind of additional military activity inside the Gulf is disruptive and has a big effect on us.

"It could have a big effect on oil prices. We've still got troops in Afghanistan, which borders Iran. And so our preferred solution here is diplomatic."

His comments echoed concerns expressed by Iran's neighbour Turkey that an attack on Iran would be disastrous.

The US President, who is up for re-election in November, has ended the US war in Iraq and is winding down combat in Afghanistan amid growing public discontent about US war spending at a time when the economy remains shaky.

He said Israel had not yet decided what to do in response to the escalating tension but was "rightly" concerned about Tehran's plans.

"My number one priority continues to be the security of the United States, but also the security of Israel, and we are going to make sure that we work in lockstep as we proceed to try to solve this, hopefully diplomatically," he told NBC.

Iranian leaders have responded sharply to speculation that Israel could bomb Iran within months to stop it from assembling nuclear weapons, threatening to retaliate against any country that launches an attack.

Iran has long maintained that its nuclear programme is designed to produce energy, despite the claims of certain western powers.

Although tough sanctions from the US and Europe have begun to inflict economic pain in Iran, its oil minister asserted on Saturday it would make no nuclear retreat even if its energy exports ground to a halt.

Betraying nervousness about the possibility of a military strike on Iran, two of its neighbours - Qatar and Turkey - urged Western powers on Sunday to make greater efforts to negotiate a solution to the nuclear dispute.

Speaking at a security conference in Munich, Turkish Foreign Minister Ahmet Davutoglu said an attack would be a disaster and suggested the dispute over Iran's nuclear programme could be ended very rapidly.

"If there is strong political will and mutual confidence being established, this issue could be resolved in a few days," he said.

"The technical disputes are not so big. The problem is mutual confidence and strong political will."