"The remains of 10 soldiers were on board the aircraft that crashed last night. There were no survivors," said a spokeswoman for the US-led military coalition, Lieutenant Tamara Lawrence.

Lawrence said all the soldiers killed in the crash in eastern Kunar province were American. Details of the dead would be released by the Pentagon, she said.

Some 15 other US soldiers have already died in Afghanistan this year, 13 of them in hostile action. Four died on March 12 when a roadside bomb ripped through their convoy in Kunar.

Friday's toll was the biggest in one incident since Taliban militants shot down another US Chinook helicopter in Kunar in June last year, killing all 16 soldiers on board, eight of them US Navy SEALs.

Two months before that a US military helicopter crashed in bad weather in the southeast of the country, killing all 18 Americans on board, including 15 service members in the worst helicopter crash during operations in Afghanistan.

The US-led coalition said the chopper that crashed on Friday was not brought down by enemy action, rejecting a claim by Taliban insurgents that they had shot it down.

"The crash occurred in a very mountainous terrain and the landing zone was very difficult. It was a mountain-top landing zone," Lawrence said.

"There were various weather factors that could have come into play... there were high winds. We are investigating any possible causes for the accident but there were no enemy actions detected at the scene."

Afghan President Hamid Karzai said in a statement he was saddened by the deaths.

"The people of Afghanistan will never forget the sacrifices made by the US soldiers for the sake of peace and prosperity of the people of Afghanistan," he said in a statement.

The aircraft was taking part in a massive anti-Taliban drive, Operation Mountain Lion, launched in insurgency-hit Kunar last month. It crashed near the provincial capital Asadabad close to the border with Pakistan.

Mountain Lion is one of the biggest operations in months against insurgents loyal to the Taliban regime. It involves 2,500 Afghan and coalition troops backed by a range of US and British war planes.

While the 20,000-soldier US-led coalition is battling Taliban and other insurgents in eastern and southern Afghanistan, a separate NATO-led force of peacekeepers is deployed in the west and north, and the capital Kabul.

Two Italian soldiers with the International Security Assistance Force (ISAF) were killed Friday and four wounded when their armoured vehicle was struck by a roadside bomb 16 kilometres (10 miles) south of Kabul.

The ISAF and coalition forces have been in Afghanistan since the ouster of the hardline Taliban government after they failed to surrender Al-Qaeda leader
Osama bin Laden after the 9/11 attacks in the United States.

Despite the coalition's efforts, there are still near-daily attacks linked to the Taliban-led insurgency and the leaders of the movement and allied Islamist groups remain on the run.

The U.S. Ambassador to the United Nations, John Bolton, dismissed the Iranian parliament's threat and said it would not deter Western nations trying to push through a new U.N. resolution demanding Tehran stop uranium enrichment.

"This is a typical Iranian threat. It shows they remain desperate to conceal that their nuclear program is in fact a weapons program," he said. "I'm confident that these statements from Iran will not deter the sponsors of the draft resolution from proceeding in the Security Council."

Bolton said he believed the resolution would move to a vote next week - with or without support from Moscow and Beijing.

The Iranian use of the word "peacefully" in the letter was seen as a reference to a diplomatic solution short of a Security Council vote and possible sanctions.

The United States is backing attempts by Britain and France to draw up a U.N. resolution that would declare Iran in violation of international law if it does not suspend uranium enrichment - a process that can produce fuel for nuclear reactors to generate electricity or, if sufficiently processed, the materials for atomic weapons.

Iran's antagonists on the issue want to invoke Chapter 7 of the U.N. charter that could lead to economic sanctions or possibly military action.

Russia and China, the other two permanent Security Council members that wield veto power oppose such action.

Iran already had stopped snap IAEA inspections, saying its 2003 agreement was being implemented voluntarily and had not been ratified by parliament and the Guardian Council, a powerful oversight body dominated by Islamic hard-liners. The protocol allows unfettered and unannounced IAEA inspections to ensure overall compliance with the NPT.

The letter, which was read on state radio, also said lawmakers would order a "review" of Article 10 of the Nuclear Nonproliferation Treaty, the section of the agreement that outlines procedures for withdrawal.

Article 10 allows signatories to pull out of the treaty if they decide that extraordinary events have jeopardized their own supreme interests. A nation wanting to withdraw must give fellow treaty signers and the U.N. three months notice and detail events leading up to the decision.

North Korea withdrew from the treaty in 2003 on that basis.

"If a signature on an international treaty causes the rights of a nation be violated, that nation will reconsider its decision and that treaty will be invalid," Ahmadinejad told the official Islamic Republic News Agency.

The U.S. and its allies "don't give us anything and yet they want to impose sanctions on us," the president said. He called threats of sanctions "meaningless" and vowed to "smash their illegitimate resolutions against a wall."

Also Sunday, Foreign Ministry spokesman Hamid Reza Asefi said again that there was nothing the international community could do to prompt Iran to suspend uranium enrichment, declaring that "intervention by the Security Council in this issue is completely illegal."

Briefing reporters, Asefi also said Iran's opponents were driven by "political motivations."

"Countries sponsoring the draft resolution (Britain, France and the United States) have political motivations," Asefi said. "It's clear that any action by the U.N. Security Council will leave a negative impact on our cooperation with the IAEA."

"Intervention by the U.N. Security Council would change the path of cooperation to confrontation. We recommend they do not do this," he said.

Iran insists its nuclear program is designed only to make fuel for reactors to generate electricity, and the IAEA says there is no evidence Iran has a nuclear weapons program.

"The U.N. Security Council should not take any action that it cannot later undo. We won't give up our rights and the issue of suspension (of enrichment) is not on our agenda," Asefi said.

Washington has had no diplomatic relations with Tehran since 1979, when the U.S. Embassy was stormed. The leaders of the two countries have not directly corresponded in that time.

The United States is leading a group of Western countries, including the European Union, in trying to stop Iran from enriching uranium.

Iran, which announced last week its uranium enrichment program was progressing well, insists its nuclear intentions are peaceful, that it only wants to generate electricity.

But other countries worry that Tehran wants to build nuclear weapons.