U.S. President Barack Obama meets with troops at Bagram Air Base in Kabul on Sunday. (Jim Young/Reuters)

U.S. President Barack Obama made an unannounced trip to Afghanistan to boost troop morale and to meet with Hamid Karzai, advising the Afghan leader to get his government in order.

Obama demanded accountability from Afghan leaders, greater vigilance against corruption and better governing as he widens the U.S. commitment to the eight-year-old war that he inherited and then dramatically escalated.

Obama said the U.S. would not quit in Afghanistan, but he made clear that he's looking for an end to direct involvement in the fight against Taliban and al-Qaeda extremists.

He drove that point home in meetings with Karzai and his cabinet during a surprise visit in Kabul on Sunday and in a speech before a cheering crowd of about 2,500 troops and civilians at Bagram Air Field north of Kabul.

At least 945 members of the U.S. military have died in Afghanistan, Pakistan and Uzbekistan as a result of the U.S. invasion of Afghanistan in late 2001, according to an Associated Press count.

The number of U.S. troops killed in Afghanistan has roughly doubled in the first three months of 2010 compared with the same period last year as Washington added tens of thousands of additional soldiers to reverse the Taliban's momentum.

"The United States is a partner but our intent is to make sure that the Afghans have the capacity to provide for their own security. That is core to our mission," Obama told the troops at Bagram, where he was greeted with thunderous applause.

The president, having changed from a suit coat to a leather Air Force One flight jacket, said he would never send Americans abroad to fight unless there was a compelling threat. He said a Taliban takeover of Afghanistan would put more Americans in danger.

"The Afghans have suffered for decades," he said, "decades of war, but we are here to help the Afghans forge a hard-won peace."

Obama's speech to the troops, delivered in a cavernous tent known as the "clam shell," was the final event on his brief, only hours-long trip that occurred entirely at night.

The trip, its secrecy forced by security concerns, was an extraordinary capstone to a momentous week in Obama's presidency. He achieved the most ambitious domestic policy initiative in decades with a historic health-care overhaul and scored his first major foreign policy achievement with a significant new arms control treaty with Russia.

Obama's aides did not try to hide U.S. impatience about Afghanistan's halting efforts to battle corruption and cronyism in government.

"The president [Karzai] needs to be seized with how important that is," said Jim Jones, Obama's national security adviser.

In public remarks at the presidential palace, Obama told Karzai and his cabinet that he was pleased with progress made since his last discussion with Karzai on March 15.

Obama invited him to visit Washington on May 12. He also praised recent steps in the military campaign against insurgents. But he stressed that Afghans need to see conditions on the ground get better.

"Progress will continue to be made … but we also want to continue to make progress on the civilian front," Obama said, referring to anti-corruption efforts, good governance and adherence to the rule of law. "All of these things end up resulting in an Afghanistan that is more prosperous and more secure," he said after a brief meeting with Karzai.

Karzai comments

Afghan President Hamid Karzai, left, and U.S. President Barack Obama inspect a guard of honour at the presidential palace in Kabul. (Jim Young/Reuters)Karzai promised that his country "would move forward into the future" to eventually take over its own security, and he thanked Obama for the American intervention in his country.

He told Obama he has begun to establish more credible national institutions on corruption and made clear he intends to make ministerial appointments more representative of the multiple ethnic and geographic regions of the country, according to a U.S. account of the meeting.

The U.S. also wants Karzai to cut the flow of money from poppy production and drug trafficking that is sustaining the insurgency. Moreover, the U.S. is pressing him to create an effective, credible judicial system and to halt cronyism and rewards for warlords in government hiring. Both of Karzai's vice-presidents are former warlords whose forces allegedly killed thousands of people in the civil war of the 1990s that paved the way for the rise of the Taliban.

The Afghan government has tried to tackle corruption in the past with little success, but Karzai pledged after fraud-marred August elections to rein in graft by making officials declare their assets and giving the country's anti-corruption watchdog more power to go after those accused of misusing their office.

This month he gave more powers to an anti-corruption body, the High Office of Oversight and Anti-Corruption, including the authority to refer cases to court and act as prosecutor.

The non-governmental organization Transparency International last year ranked Afghanistan 176th out of 180 countries in its annual poll that assesses the degree to which corruption is perceived to exist among public officials and politicians. The only countries ranked lower were Haiti, Iraq, Myanmar and Somalia.

In December, Obama ordered 30,000 additional forces into the fight against the Taliban, which lost control of the country when the U.S. invaded in 2001. Those new U.S. troops are still arriving and most are expected to be in place by summer for a full force of roughly 100,000 U.S. troops. There were about 34,000 when Obama took office.

The war is unpopular with a majority of Americans, especially progressives in the base of Obama's Democratic Party. This was reflected in Obama's new Afghanistan strategy. He combined the large buildup — his second to the Afghanistan force in less than a year as president — with a call to start bringing troops home in July 2011, just a year after the full contingent is in place.