DAVOS, Switzerland (Reuters) -- An attack on Iran would be catastrophic for its nuclear program, Mohamed ElBaradei, director general of the International Atomic Energy Agency, said on Thursday.

"It would be absolutely counterproductive, and it would be catastrophic," ElBaradei said at a discussion on nuclear proliferation at the World Economic Forum.

The Bush administration in recent weeks has toughened its stance against Iran.

President George W. Bush has moved an additional aircraft carrier into the Persian Gulf.

ElBaradei, head of the UN's nuclear watchdog, has been engaged in meetings here at the gathering of world political and business leaders. He said diplomacy is the only way forward, and talk of military action can only backfire.

The Bush administration has said it wants a diplomatic solution and that it is not preparing to attack either Iran or Syria.

Pakistan's Prime Minister Shaukat Aziz also warned against an attack, while Iran's former president Mohammad Khatami urged calm to reduce tensions over Iran's nuclear program.

"If there is military action, it will have catastrophic results, not only in the region, but the whole world," Aziz said.

"I hope they would be good enough in managing the situation. We deeply need patience and understanding and not to get too emotional," Khatami said. "I am convinced that the only way forward in Iran is engagement," ElBaradei said.

"We have to invest in peace," he said, adding that if the international community failed to do that "the consequence will be 10 times worse."

"I hope we will stop speaking about a military option and focus on finding a solution," ElBaradei said.

Iran says it needs nuclear power to generate electricity.