WASHINGTON — President Barack Obama on Tuesday ended the U.S. combat mission in Iraq, declaring no victory after seven years of bloodshed, and telling Americans and the world: "It is time to turn the page."

From the Oval Office, where George W. Bush first announced the invasion that would come to define his presidency, Obama addressed millions who were divided over the war in his country and around the world. Fiercely opposed to the war from the start, he said the United States "has paid a huge price" to give Iraqis the chance to shape their future.

In a telling sign of the domestic troubles weighing on the United States and his own presidency, Obama turned much of the emphasis in a major war address to the dire rate of U.S. joblessness.

The speech, lasting slightly less than 20 minutes, was only his second address from the Oval Office. Obama looked directly into the TV camera, hands clasped in front of him on his desk, family photos and the U.S. and presidential flags behind him.

Even as he tries to cap one of the most divisive chapters in recent American history, Obama is escalating the conflict in Afghanistan. He pledged anew that the United States would keep up the fight in that war, the longest once since Vietnam.

In Iraq, for all the finality, the war is not over. More Americans probably will die. The country is plagued by violence and political instability, and Iraqis struggle with constant shortages of electricity and water.

Obama is keeping up to 50,000 troops in Iraq for support and counterterrorism training, and the last forces are not due to leave until the end of 2011 at the latest.

As the commander in chief over a war he opposed, Obama took pains to thank troops for their sacrifice but made clear he saw the moment more as a mistake ended than a mission accomplished. He spoke of strained relations with allies, anger at home and a "huge price" of the highest order.

The toll includes more than 4,400 U.S. troops dead and many more Iraqis, tens of thousands more Americans wounded, and hundreds of billions of dollars spent.

To underscore his point of ending the divisiveness over Iraq, Obama said he had called Bush, whom he had taunted so often in the 2008 presidential campaign. He prominently praised the former Republican president in the heart of his speech.

"It's well known that he and I disagreed about the war from its outset," Obama said. "Yet no one could doubt President Bush's support for our troops, or his love of country and commitment to our security."

In the aftermath of the Sept. 11, 2001 terrorist attacks, the Iraq war began with bipartisan congressional backing, based on what turned out to be flawed intelligence that Iraq was stockpiling weapons of mass destruction.

Today, Iraq is in political turmoil, its leaders unable to form a new government long after March elections that left no clear winner. The uncertainty has created an opening for insurgents to pound Iraqi security forces, hardly the conditions the United States envisioned for this transition deadline, which Obama announced 18 months ago.

Obama pressed Iraq's leaders, saying it was time to show some urgency and be accountable.

At once, Obama sought to assure Americans that the war was finally winding down, and yet also promise Iraq and those watching across the Middle East that the U.S. was not simply walking away.

"Our combat mission is ending," he said, "but our commitment to Iraq's future is not."