The U.S. war on terror in Afghanistan is on track, and the United States will remain in the country carrying out combat operations and reconstruction projects "for as long as it takes," the U.S. general overseeing the war said Friday.

Speaking to reporters at Bagram Air Base, the headquarters of U.S and coalition military operations in Afghanistan, Gen. Tommy Franks said U.S.-led efforts to root out al-Qaeda and Taliban remnants in Afghanistan were maintaining their momentum. As commander of U.S. Central Command, Franks oversees all U.S. troops in the Middle East and Central Asia.

Attacks and hostile incidents on U.S. and coalition forces in Afghanistan in the past three months have increased. On Wednesday, a U.S. special forces soldier was shot and wounded in an ambush and on Thursday, gunmen fired as many as five rockets at a U.S. base in southeastern Afghanistan.

Most of the top al Qaeda and Taliban leaders are still at large.

"While an awful lot has been done in Afghanistan, this is Afghanistan. We're just going to have to stay with it for as long as it takes ... to be sure that we don't permit terrorism to retake Afghanistan," Franks said.

Franks refused to say whether the U.S. mission was evolving into one of "nation-building" -- a term some U.S. political and military leaders say is better left to the United Nations or other organizations.

U.S. forces routinely offer humanitarian assistance and medical aid to Afghan villages. Civil affairs officers also travel with combat troops to query villagers about development needs, like drinking water and agriculture.

"We're talking about modifying the focus of what we put into (military operations) ... and how much we put into the business of reconstruction," Franks said.

Franks, who met with U.S. troops serving in Kuwait and Kyrgyzstan on Thursday, said the U.S.-led war of terrorism remains on track around the world, and said fewer terrorists were on the streets than before Sept. 11.

"That doesn't mean that we don't have a long road in front of us" Franks said. "We still see terrorist operations on this planet and we're going to continue to see them for a long, long time."

Franks is visiting countries playing major roles in the hunt for al-Qaida terrorists and their Taliban supporters in Afghanistan.

In Saudi Arabia earlier this week Franks met with senior defense officials in Riyadh and visited American troops at Prince Sultan air base, which includes an air operations center from which U.S. commanders orchestrated the air campaign over Afghanistan.