The United States is in no position to attack Iran because it is bogged down in the conflict in Iraq, Iranian Foreign Minister Manouchehr Mottaki said on Saturday.

Mottaki was talking at the sprawling Iranian consulate in the western Afghan city of Herat, on the border with Iran, where a regional trade conference was taking place.

"Americans have never been in such a grave situation and this is because of their own deeds," he said with a smile.

U.S. officials say Iran supports the Shi'ite militias in Iraq and may be involved in sending arms to the resurgent Taliban in Afghanistan.

Washington also accuses Tehran of building nuclear weapons and has not ruled out an attack against it.

Iran has denied the accusations and Afghanistan, where U.S. forces make up the majority of foreign troops, says it has no evidence that Tehran is involved in arming the Taliban.

"Since the actual probability of the subject is nil, therefore one cannot talk about it," Mottaki told a press conference when asked if Iran would hit U.S. bases in Afghanistan should Washington launch an attack against it.

Washington thought it could dictate to the world as the only superpower after the collapse of the Soviet Union, Mottaki said.

"America, today, in the international system is facing a serious challenge ... Americans are in a very, very difficult situation.

"The people of Afghanistan would not allow America to use Afghanistan against any country. This is our ... belief," he said.

Mottaki said Tehran's findings from three rounds of talks with U.S. officials on the situation in Iraq was that Washington was facing "very serious" difficulties there.

Washington has no exit strategy from Iraq and is bogged down in the conflict there. He said the U.S. had not managed to deliver on its promises to the Afghan people either.

"Therefore, we do not see such a probability that the Americans would want to attack ... another country in the region. They are not in such a position."