John Kerry (search) aimed a new volley of criticism at President Bush's (search) handling of the situation in Iraq on Saturday, saying Bush's failure to "internationalize" the conflict has made America less safe and cost it credibility and momentum.

"Our stubborn, unilateral policy in Iraq has steadily drifted — from tragedy to tragedy," the presumptive Democratic presidential nominee said in his party's weekly radio address.

Kerry called for a new approach that would put greater reliance on other nations, but conceded "it won't be easy to get our friends and allies to send in new troops."

The Massachusetts senator said that while the United States should not retreat from Iraq in disarray, "staying the course does not mean stubbornly holding to the wrong course. In order to complete our mission, we must review our tactics."

Kerry called for removing the "Made in America" label from the Iraqi operation by creating an international mission authorized by the United Nations (search) to help set up elections, restore government services and rebuild the economy.

"The failure of the administration to internationalize the conflict has lost us time, momentum and credibility — and made America less safe," Kerry said.

Bush has been hoping to put a more international face on the U.S.- and British-dominated coalition. On Friday, he welcomed a proposal from U.N. Iraq envoy Lakhdar Brahimi (search) on transferring sovereignty and called Brahimi's outline "a way forward to establishing an interim government that is broadly acceptable to the Iraqi people."

Earlier this week, Bush said he would like to get a new U.N. resolution "that will help other nations to decide to participate" in Iraq.

Kerry voted for the 2002 congressional resolution that authorized Bush to use force in Iraq. But since the U.S. invasion a year ago he has become increasingly critical of Bush's war management.