US Democratic presidential candidate John Kerry on Friday proposed replacing the US-led military force in Iraq with a Nato force under US command.
That way "American soldiers and the American people are not bearing nearly all the burden and all the risk," Kerry said in a statement.
"It is possible to transform the US force into a Nato force, commanded by an American," said the man seeking to unseat President George W. Bush in the November 2 election.
"We should send a high-level mission to consult with our Nato partners to encourage their participation and get other countries to participate.
"We have to succeed in Iraq," said Kerry. "We simply can't allow it to become a failed state. That would mean a victory for extremism, new dangers in the Middle East and a breeding ground for anti-American terrorism.
"To succeed, we are going to need more forces on a temporary basis. Our commanders on the ground have requested it. We should provide it."
He said the United States should seek a UN Security Council resolution authorising a UN mission with responsibility for the transition and elections. "We need a plan for the period after June 30 when the interim government takes control," he said.
"We should establish an international mission authorised by the UN to work with the interim government on governance issues, including elections and the reconstruction of Iraq and rebuilding the Iraqi economy," the statement read.