WASHINGTON — Warning that the United States could lose the war in Afghanistan, the chairman of the Joint Chiefs of Staff announced Wednesday that he'd ordered a "more comprehensive" strategy there to address the growing cross-border insurgency.

Testifying on Capitol Hill, Adm. Michael Mullen gave a blunt assessment of the U.S. effort in Afghanistan: "I am not convinced that we're winning it in Afghanistan. I'm convinced we can."

Mullen and Secretary of Defense Robert Gates appeared before the House Armed Services Committee a day after President Bush announced that the U.S. would increase its presence in Afghanistan by 1,500 troops. Gates, who focused on Iraq, told the committee he thought that the U.S. strategy in Iraq has "entered that end game."

Their testimony was a public airing of a discussion that's going on within the Pentagon about how quickly the military can shift its focus from Iraq to Afghanistan. While violence has dropped precipitously in Iraq, it's climbed in Afghanistan. U.S. troop deaths there are higher than Iraq now, despite a far smaller presence. In addition, insurgent groups increasingly are taking control of villages.

To increase troops in Afghanistan, the U.S. must reduce them in Iraq.

However, Gen. David Petraeus, the top American commander in Iraq, has recommended a slow withdrawal to maintain the improvements from the troop buildup, and Bush on Tuesday announced a drawdown of only 8,000 troops weeks after his presidency ends.

There are currently 146,000 U.S. troops in Iraq.

Gen. David D. McKiernan, the top U.S. commander in Afghanistan, asked for three more brigades, but Bush promised Tuesday only to send one. Because other service members will be leaving, the net increase there will be 1,500 troops, to about 35,000.

Within the Pentagon, Mullen has been the most outspoken proponent of sending more resources to Afghanistan to deal with the growing insurgency there, particularly along the Afghan-Pakistani border. He's met on several occasions with Pakistani army Chief Gen. Ashfaq Kayani, including a visit last month aboard a U.S. naval carrier.

"Frankly, we are running out of time," Mullen said, adding that Bush's announcement was a "good start."

With the military so focused on Iraq, its strategy in Afghanistan has been unclear, other than to train the Afghan security forces and support the government. Mullen said the new strategy would address threats from neighboring Pakistan.

Afghanistan and Pakistan "are inextricably linked in a common insurgency that crosses the border between them," Mullen said.

While Mullen stressed the needs in Afghanistan, Gates emphasized the continuing U.S. commitment to stabilizing Iraq. Success, he said, is when the American military is "steadily reducing our commitment, our level of commitment and resources, particularly manpower, to that theater."

At the same time, he said "we should expect to be involved in Iraq for years to come."

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