U.S. military forces are closely monitoring an area in eastern Afghanistan where reports suggest al-Qaida fighters may again be trying to regroup.

The area is around the eastern Afghan town of Khost, close to the Pakistani border and less than 100 kilometers from the Shah-i-Kot region where American, Afghan and other coalition troops battled al-Qaida and Taleban fighters for more than two weeks.

Air Force Brigadier General John Rosa of the Pentagon's Joint Staff stops short of telling reporters there is a new build-up of al-Qaida and Taleban forces there, but he describes conditions as tense. "It remains a dangerous place," he said. "We are continuing to surveil that area, gather intelligence and to characterize that now is, I think, probably inappropriate."

Chief Pentagon spokeswoman Victoria Clarke says U.S. military planners continue to expect to find what she calls pockets of al-Qaida and Taleban resistance, even though most of the major fighting in Afghanistan is over. "But it's always worth repeating we expect and anticipate additional pockets of resistance," she said. "It is the MO [modus operandi] of these people to try to regroup in some shape or fashion."

Still the Pentagon is discounting new reports indicating al-Qaida leader Osama bin Laden and a top aide have been spotted recently in the Khost area. Officials say U.S. troops continue to search for bin Laden but they say none of the recent reports on his whereabouts have proved credible.

Meanwhile, defense officials say they will work closely with Afghan authorities to determine the kinds of relief aid the United States can provide in the wake of the latest earthquake to rock Afghanistan.

They also say there have been no reports of U.S. or other coalition troops killed or injured in the quake.