The top-ranking Republican in the U.S. Senate on Sunday expressed frustration with the Iraqi government, saying Republicans were "overwhelmingly disappointed" with the lack of political progress.

"The Iraqi government is a huge disappointment," Senate Minority Leader Mitch McConnell told CNN'S Late Edition on Sunday.

"So far, they've not been able do anything they promised on the political side," the Kentucky Republican said, citing the Iraqis' failure to pass a new oil revenue bill, hold local elections and dismantle the former Baath Party of Saddam Hussein. "It's a growing frustration."

"Republicans overwhelmingly feel disappointed about the Iraqi government," he added.

McConnell spoke as the Senate is trying to approve funding for the Iraq war with a compromise that President George W. Bush can sign. Bush has threatened to veto a bill passed by the U.S. House of Representatives that provides only enough money to continue combat for two or three months.

McConnell said there was a growing sense of frustration across all political divides in the U.S. Senate with failures of the Iraqi government.

"I don't know what their problem is but this country has made an enormous investment in giving the Iraqis a chance to have a normal government after all of these years of Saddam Hussein and his atrocities," he said.

Citing media reports, McConnell said some lawmakers in Iraq's parliament wanted a vote to ask the United States to leave.

"I want to assure you, if they vote to ask us to leave, we'll be glad to comply with their request," he said.

McConnell's comments came as a group linked to al Qaeda claimed in an Internet message to have seized three U.S. soldiers in an ambush south of Baghdad and a suicide truck bombing killed 50 people in the Kurdish north.

McConnell made no apology for the U.S. invasion in Iraq and Afghanistan following the September 11, 2001, attacks on the United States.

"I think Republicans believe overwhelmingly, is that the decision to get on offense in the war on terror after 9/11 in Afghanistan and Iraq has protected us fully here at home," McConnell said.

"What we are all discovering, however, it's very difficult to set up a functioning government in places like Iraq and Afghanistan."

The United States should consider whether the threat from al Qaeda would be increased at home if its troops withdrew from Iraq, he said.

"If we give up prematurely, we go home, declare it over, will they be back here on the -- in our own country?" McConnell said. "And I think the chances of that are overwhelmingly likely."