Democrat presidential hopeful John Kerry has accused President Bush of failing to do enough to get the world support needed to win peace in Iraq.
Kerry called for a new UN-backed mission to help rebuild Iraq
In a weekly radio address to Democrats Mr Kerry said the Bush administration had to change its strategy in Iraq.
This month has seen a surge of violence and kidnappings of foreigners in Iraq, including an American soldier.
Jordan's King Abdullah II has said the presence of US troops in Iraq has led to great animosity in the Arab world.
The king, in the US for talks with Mr Bush, said the feeling "being felt toward the United States around the region and around the world is not a healthy one".
Meanwhile, Mr Kerry called for a new UN-backed mission to help rebuild Iraq, with a Nato security force under US command keeping order.
US casualties this month are the heaviest since the conflict started
"The president may not want to admit mistakes, but his choices in Iraq have so far produced a tragedy of errors," he said.
"Staying the course does not mean stubbornly holding to the wrong course."
In the address, taped in Pittsburgh, on Friday, he added: "The failure of the administration to internationalise the conflict has lost us time, momentum and credibility and made America less safe."
The BBC's Jannat Jalil, in Washington, this is an attempt by John Kerry, just seven months before an election that's too close to call, to show how he would deal with the mounting violence and casualties in Iraq.
The volatile situation there could become one of the most important issues in this year's presidential election campaign.
This is a big concern for the current administration as the latest opinion polls indicate public support for Mr Bush's handling of Iraq is slipping.
But it is hard to see countries sending troops to Iraq given the current violence there and President Bush has already embraced the plan that would give the United Nations a more prominent role in Iraq, our correspondent adds.
King Abdullah II, an ally of the United States, will hold talks with President Bush in Washington next week.