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U.S. readies for next mission after Anaconda

Soldiers from the U.S. Army's 101st Division arrive in Kandahar, Afghanistan, after taking part in Operation Anaconda.

BAGRAM AIR BASE, Afghanistan (CNN) -- With Afghan fighters taking the lead on the ground in the mountains of Paktia province in eastern Afghanistan, U.S. troops prepared to turn their attention to pockets of opposition elsewhere in the country, officials said Tuesday.

U.S. airstrikes hammered away Tuesday at al Qaeda positions, and Afghan military commanders reported their troops seized two key sites and were making progress on others.

A senior U.S. military official in Washington said nearly 600 American troops -- almost half the U.S. ground force participating in Operation Anaconda -- had withdrawn. Most of the U.S. troops were at Bagram air base north of the Afghan capital, Kabul, and could be sent to fight against other areas of al Qaeda and Taliban members.

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None of these additional pockets -- mainly in southeastern Afghanistan -- are thought to be as large as the one near Gardez, provincial capital of Paktia, where the United States has been battling for more than a week, the official said.

The United States is conducting reconnaissance and intelligence against the additional areas to get a better idea of how many al Qaeda and Taliban members may be in each, the official said. The initial estimate was that 200 enemy fighters were near Gardez, but within days it had grown to 1,000.

After 10 days of bombing and intense ground fights, the United States estimates there are fewer than 200 al Qaeda holdouts left in the mountains near Gardez. Eleven allied troops -- including eight Americans -- and more than 450 al Qaeda and Taliban fighters have been killed in the operation.

"Enemy resistance continues to be light," said Maj. Bryan Hilferty, a spokesman for the 10th Mountain Division. "In fact, we have not received accurate or sustained enemy fire for more than five days."

The U.S. military official in Washington confirmed that remnants of al Qaeda forces have fled the area, with some perhaps moving south or across the border into Pakistan. However, details are hard to determine, he said. Afghan officials said the operation is over and claimed victory.

U.S. soldiers fire mortar at suspected al Qaeda and Taliban strongholds in Afghanistan.

U.S. soldiers returning to Bagram said fighting in the mountains against a resolute enemy was difficult, but they were equally determined.

"It was pretty intense the first couple of days," said Army 1st Sgt. Scott Schroeder, who had returned to Bagram with most of his unit but had one platoon under his command in the mountains. "But after that it was sporadic."

Schroeder had high praise for his men.

"Initially getting off they had a little anticipation, but once they started receiving fire ... they reacted quickly," he said.

Schroeder, a Persian Gulf War veteran, said the battle in the Afghan mountains was "much more close and personal" than the fight in Iraq.

"You could see the people shooting at you," he said.

CNN Correspondents Barbara Starr and Martin Savidge contributed to this report.