BAGRAM AIR BASE, Afghanistan ? Defense Secretary Robert Gates suggested Wednesday he would ask President Bush to send more troops to Afghanistan, an increase that could intensify pressure on a U.S. military already straining to wage the war in Iraq.

After two days of talks with American, NATO and Afghan officials, Gates said he was impressed with progress toward stabilizing and rebuilding Afghanistan. Yet he also said military commanders want to add U.S. troops to the 24,000-strong American force now there, the highest level of a five-year-old war.

While Gates used no figures, a senior official traveling with him said the prospective increase would not be large – possibly one or two battalions, no more than a couple of thousand soldiers. The official spoke on condition of anonymity because no decision had been made.

Gates stopped short of saying he would recommend the increase. Yet he offered a rationale for reinforcing a war effort that has seen the quick toppling of the Taliban rulers of a country that had been sanctuary for al-Qaida leader Osama bin Laden, only to have combat flare in recent months with renewed Taliban attacks.

“I think it is important that we not let this success here in Afghanistan slip away from us and that we keep the initiative,” he told reporters traveling with him. “There’s no reason to sit back and let the Taliban regroup.”

A U.S. troop increase in Afghanistan would come on top of Bush’s decision to send 21,500 more soldiers and Marines to Iraq over the coming four months – adding to the roughly 132,000 already there. That boost had been opposed by many Pentagon uniformed officers, who worry that it would be too much stress on a force that is already sending soldiers to Iraq for multiple tours.

The two wars, each now longer than U.S. involvement in World War II, have stretched American land forces so thin that the Army and Marines are requesting tens of billions more in funding and have persuaded Bush to ask Congress to increase their size.

Gen. Peter Pace, chairman of the Joint Chiefs of Staff, said new troop commitments for Afghanistan would further strain the U.S. military in the short run. But if done as part of a successful strategy against the Taliban, it might hasten the day when the U.S. military can withdraw its combat forces altogether, said Pace, who joined Gates for part of his Mideast trip.

Gates said the number of extra troops “depends on different scenarios,” which now will be examined.