The United States and the Iraqi government are launching a new diplomatic initiative to invite Iran and Syria to a "neighbors meeting" on stabilizing Iraq, Secretary of State Condoleezza Rice said Tuesday.

"We hope these governments seize this opportunity to improve their relations with Iraq and to work for peace and stability in the region," Rice said in remarks prepared for delivery to a Senate committee. Excerpts were released in advance by the State Department.

The move reflects a change of approach by the Bush administration, which previously had resisted including Iran and Syria in diplomatic talks on stabilizing Iraq.

"I am pleased to announce that we are also supporting the Iraqis in a new diplomatic offensive: to build greater support, both within the region and beyond, for peace and prosperity in Iraq," Rice said, adding that U.S. and Iraqi officials agree that success in Iraq "requires the positive support of Iraq's neighbors."

At the White House, press secretary Tony Snow told reporters the administration is "happy that the government of Iraq is taking this step and engaging its neighbors. And we also hope and expect that Iran and Syria will play constructive roles in those talks."

But Snow cautioned people to be patient, noting that "this is one where the agenda is being set up by the government of Iraq. And the conditions, especially for bilateral conversations with the Iranians, are pretty clear."

The administration in recent weeks had increased its public criticism of Iran's role in Iraq, charging it with supplying deadly weapons, including advanced technologies for the most lethal form of roadside bombs. The administration also has accused Syria of harboring anti-Iraqi government forces and allowing weapons to cross its border.

Rice and Defense Secretary Robert Gates were testifying Tuesday before the Senate Appropriations Committee on the administration's budget request for the wars in Iraq and Afghanistan.