BAGHDAD – As the U.S. winds up combat operations in Iraq this month, a gap is widening between the militaries of both countries and their political masters over whether American soldiers should stay beyond the 2011 deadline for a complete U.S. troop withdrawal.

It's the latest friction as the uneasy allies try to end the seven-year U.S. war without unraveling Iraq's precarious security.

A security agreement between the two nations calls for all U.S. troops to leave Iraq by the end of 2011. By Sept. 1, only 50,000 American soldiers will remain in the country, their combat authority strictly curtailed in the largest step to date toward the 2011 deadline.

Mindful of their campaign promises, both Prime Minister Nouri al-Maliki and aides to President Barack Obama this week declared that this summer's withdrawal indeed marks the beginning of the end of U.S. troops in Iraq.

"This commitment will end on the scheduled date, as agreed," al-Maliki said Thursday at a meeting of Iraqi defense officials in Baghdad.

Not so fast, said Gen. Babaker Shawkat Zebari, the Kurd who commands Iraq's military, warning again Wednesday that his army may not be ready to defend the nation until 2020.

Zebari first aired those concerns in an Associated Press interview in June, in which he indicated it could be a decade or more before his soldiers can take full control of security in Iraq.

"If it was in my hands, from the military perspective of the job, I would have asked them to keep some American bases in the country" until then, he told the AP.

The gap was also on full display in Washington this week.

The White House defiantly maintained Wednesday that all troops — save those working with the U.S. Embassy and other diplomatic outposts — will be out of Iraq by the end of next year, just as Obama gears up for the 2012 presidential election campaign.

"We have every intention of fulfilling that agreement by end of 2011," Deputy National Security Adviser Ben Rhodes told reporters. "All systems in the United States government are planning towards getting down to no troops at the end of 2011, consistent with that agreement."

But within hours, while talking to Pentagon reporters en route to a military ceremony in Tampa, Fla., Defense Secretary Robert Gates left open the door that troops could stay in Iraq as long as Baghdad asks for them.

"We have an agreement with the Iraqis that both governments have agreed to that we will be out of Iraq at the end of 2011," Gates said. "If a new government is formed there and they want to talk about beyond 2011, we're obviously open to that discussion."

"But that initiative will have to come from the Iraqis," he said.

At the height of the U.S. military surge in 2007, nearly 170,000 American forces were in Iraq. The security agreement that outlined their phased-out departure could be re-negotiated to allow U.S. troops to remain if, as Gates said, Iraq's leaders demand it.

That decision may not be up to al-Maliki, who has been grasping to retain enough support to remain as prime minister since his slate came in a close second in March parliamentary elections to a Sunni-dominated political alliance.

Even if Iraq's government asks for U.S. troops to stay, there's no guarantee the Obama administration will agree to it.

Doing so would likely infuriate Democrats within Obama's political base after he promised during his 2008 campaign to end what he termed "a dumb war." Obama already has his hands full with the other, longer war — in Afghanistan — and with Republicans on Capitol Hill who are pummeling him with nearly nonstop criticism of his handling of it.

Bombings continue almost daily in Baghdad and around the rest of Iraq — a grim reality illustrated by the fact that the number of civilians killed by insurgents in July was the highest in two years. Though violence is far lower than it was between 2005 and 2007, when revenge attacks by Sunnis and Shiites brought the country to the edge of civil war, Iraq is far from secure.

Even al-Maliki acknowledged Thursday that U.S. aid — largely for an estimated 660,000 Iraqi troops, police forces and government-backed militias — will be needed far beyond 2011 to make Iraq safe.

"Despite accomplishing big progress in building these forces, they need more training, more rehabilitation and secure equipment," he said.

Ultimately, it's political leaders who make the final call, and without repeated spectacular attacks that signal the return of sectarian violence, there's little reason for al-Maliki or the White House to budge from the 2011 timeline.

"Right now, it makes no sense for the White House to rethink the policy, and there's no political advantage for Maliki to signal weakness or vacillation when that decision doesn't have to be made today and the reality isn't yet clear," said Juan Zarate, a fellow at the Center for Strategic and International Studies who sat on the National Security Council during the Bush administration.

But he predicts "a serious debate" down the road on whether to keep troops in Iraq — especially if their departure could lead to Iranian meddling and threaten American interests in the Mideast.

"The military guys are being more cautious because they understand that the security conditions may shift in a way that requires a continued presence," Zarate said. "You may see a move from this strict 'No troops in Iraq' mantra."