WASHINGTON, (AP) – The Bush administration is attempting to re-energize its terrorism-fighting war efforts in Afghanistan, the original target of a post-Sept. 11 offensive. The U.S. also is refocusing on Pakistan, where a regenerating al-Qaeda is posing fresh threats.

There is growing recognition the United States risks further setbacks, if not deepening conflict or even defeat, in Afghanistan, and that success in that country hinges on stopping Pakistan from descending into disorder.

Privately, some senior U.S. military commanders say Pakistan’s tribal areas are at the center of the fight against Islamic extremism; more so than Iraq, or even Afghanistan. These areas border on eastern Afghanistan and provide haven for al-Qaeda and Taliban fighters to regroup, rearm and reorganize.

This view may explain, at least in part, the administration’s increasingly public expressions of concern.

At a Pentagon news conference last week, Defense Secretary Robert Gates said that while the U.S. respects the Pakistani government’s right to decide what actions are needed to defeat extremists on its soil, there are reasons to worry that al-Qaeda poses more than an internal threat to Pakistan.

The Pentagon says it has fewer than 100 troops in Pakistan, including personnel who are training Pakistan’s paramilitary Frontier Corps along the Afghanistan border.

The U.S. military has used other means, including aerial surveillance by drones, to hunt Osama bin Laden and other senior al-Qaeda leaders believed to be hiding near the Afghan border. Ground troops on the Afghan side sometimes fire artillery across the border at known Taliban or al-Qaeda targets, and U.S. officials have said special operations forces are poised to strike.

In recent days, administration officials have said they would send more U.S. forces if the Pakistani government decided it wanted to collaborate more closely. Still, it is far from certain that U.S. combat troops will set foot in Pakistan in any substantial numbers. On Friday, Pakistan’s president, Pervez Musharraf, said his country opposes any foreign forces on its soil.