WASHINGTON • President Barack Obama declared an end Tuesday to the seven-year U.S. combat mission in Iraq, saying that the United States has met its responsibility to that country and that it is now time to turn to pressing problems at home.

In a prime-time address from the Oval Office, Obama balanced praise for the troops who fought and died in Iraq with his conviction that getting into the conflict had been a mistake in the first place. He also used the moment to emphasize that he sees his primary job as addressing the weak economy and other domestic issues and to make clear that he intends to begin disengaging from the war in Afghanistan next summer.

"We have sent our young men and women to make enormous sacrifices in Iraq, and spent vast resources abroad at a time of tight budgets at home," Obama said. "Through this remarkable chapter in the history of the United States and Iraq, we have met our responsibility. Now, it's time to turn the page."

Seeking to temper partisan feelings over the war on a day when Republicans pointed out that Obama had opposed the troop surge generally credited with bringing Iraq a measure of stability, the president offered some praise of his predecessor, George W. Bush. Obama acknowledged their disagreement over Iraq but said that no one could doubt Bush's 'support for our troops, or his love of country and commitment to our security."

With his party facing the prospect of losing control of one or both houses of Congress in this fall's midterm elections and his own poll numbers depressed in large part because of the lackluster economy and still-high unemployment, Obama said the nation's perseverance in Iraq must be matched by determination to address problems at home.

Over the past decade, "we have spent over a trillion dollars at war, often financed by borrowing from overseas," he said. "And so at this moment, as we wind down the war in Iraq, we must tackle those challenges at home with as much energy and grit and sense of common purpose as our men and women in uniform who have served abroad."

Obama acknowledged a war fatigue among Americans who have called into question his focus on the Afghanistan war, now approaching its 10th year. He said that U.S. forces in Afghanistan "will be in place for a limited time" to give Afghans the chance to build their government and armed forces.

"But, as was the case in Iraq, we cannot do for Afghans what they must ultimately do for themselves," the president said.

He reiterated that in July he would begin transferring responsibility for security to Afghans, at a pace to be determined by conditions on the ground.

"But make no mistake: This transition will begin, because open-ended war serves neither our interests nor the Afghan people's," he said.

This was no iconic end-of-war moment with photos of soldiers kissing nurses in Times Square or victory parades down America's Main Streets.

Instead, in the days leading to the Tuesday night deadline for the withdrawal of U.S. combat troops from Iraq, it has appeared as if administration officials and the U.S. military were the only ones marking the end of this country's combat foray into the area once known as the cradle of civilization. Vice President Joe Biden, Defense Secretary Robert Gates and Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, are all in Baghdad for the official ceremony Wednesday morning.

The very sight of Obama addressing Americans from the Oval Office — from the same desk where Bush announced the beginning of the conflict — shows the distance traveled since the Iraq war began. On the night of March 20, 2003, when the miles-long convoy of the Army's 3rd Infantry Division first rolled over the border from Kuwait into Iraq, Obama was a state senator in Illinois.

Bush was at the height of his popularity, and the perception at home and in many places abroad was that America could achieve its national security goals primarily through military power. One of the biggest fears among the U.S. troops in the convoy pouring into Iraq that night — every one of them suited in gas masks and wearing biohazard suits — was that the man they came to topple might unleash a chemical weapons attack.

Seven years and five months later, the biggest fears of U.S. soldiers revolve around the primitive, basic, homemade bombs and old explosives in Afghanistan that were left over from the Soviet invasion. In Iraq, what was perceived as a threat from a powerful dictator, Saddam Hussein, with an iron grip of control, has dissolved into the worry that as U.S. troops pull out, they are leaving behind an unstable and weak government that could be influenced by Iran.

On Tuesday, a senior intelligence official said that Iran continues to supply militant groups inside Iraq with weapons, training and equipment.

"Much has changed since that night," when Bush announced the war in Iraq from the Oval Office, Obama said. "A war to disarm a state became a fight against an insurgency. Terrorism and sectarian warfare threatened to tear Iraq apart. Thousands of Americans gave their lives; tens of thousands have been wounded. Our relations abroad were strained. Our unity at home was tested."

The withdrawal of combat forces represents a significant milestone after the war that toppled Saddam, touched off waves of sectarian strife and claimed the lives of more than 4,400 U.S. soldiers and more than 70,000 Iraqis.

As Obama prepared to observe the end of one phase of the war, he called Bush, who led the nation into the conflict, from Air Force One as he was en route to Fort Bliss in Texas to meet with U.S. troops home from Iraq.

The two spoke "just for a few moments," Ben Rhodes, deputy national security adviser for strategic communications, told reporters aboard the plane, declining to give any additional details about the conversation.

U.S. troops reached Obama's goal for the drawdown early — last week Gen. Ray Odierno, the U.S. commander in Iraq, said that the number of troops had dropped to 49,700, roughly the number that would stay through next summer.

That is less than a third of the number of troops in Iraq during the surge in 2007. Under an agreement between Iraq and the United States, the remaining troops are to leave the country by the end of 2011.

The remaining "advise and assist" brigades will officially concentrate on training Iraqi security forces, protecting U.S. personnel and facilities and mounting counterterrorism operations.