Republican presidential candidate John McCain played down reports Tuesday that Iraqi officials are increasing pressure on the United States to agree to a specific timeline to withdraw its forces.

McCain said he was confident the government of Prime Minister Nouri al-Maliki would ask American troops to leave only if the military situation there warranted such a move.

"I know for a fact that it will be dictated by the situation on the ground, as it always has been," McCain said.

"Since we are succeeding" in Iraq, he said, "then I am convinced, as I have said before, we can withdraw and withdraw with honor, not according to a set timetable. And I'm confident that is what Prime Minister Maliki is talking about, since he has told me that for the many meetings we have had."

The increased pressure from Iraq comes as time is running out for the Bush administration to reach a needed troop deal. Some type of agreement is needed to keep U.S. troops in Iraq after a U.N. mandate expires Dec. 31.

McCain opposes scheduling a troop withdrawal. Democratic candidate Barack Obama promises to remove troops within 16 months of taking office.

An Iraqi proposal for a timeline that was made public Tuesday appears to set an outer limit, requiring U.S. forces to fully withdraw five years after the Iraqis take the lead on security nationwide.

"We will not accept any memorandum of understanding that doesn't have specific dates to withdraw foreign forces from Iraq," Iraq's national security adviser, Mouwaffak al-Rubaie, said Tuesday.