An Al Qaeda-operated bomb factory and a crude biological weapons research site were discovered by U.S. forces in Afghanistan, officials said Saturday.

Gen. Tommy Franks, head of U.S. Central Command, said that U.S. forces recently found evidence in Afghanistan that suspected terrorist leader Usama bin Laden was trying to "get his hands on" anthrax or other biological weapons.

The troops found nothing, though, to show that bin Laden's Al Qaeda network had succeeded in obtaining anthrax or making germ weapons.

Franks made the comments to NBC during the taping of Meet the Press, which airs Sunday.

Franks said U.S. forces recently discovered a site near the southern Afghan city of Kandahar that appeared to be an Al Qaeda biological weapons lab under construction.

The site near Kandahar was one of 50 to 60 possible Al Qaeda weapons sites in Afghanistan examined by U.S. forces, Franks and Pentagon spokesman Bryan Whitman said Saturday. Those searches found extensive evidence that Al Qaeda wanted to develop biological weapons, but came up with no evidence the terrorist group actually had anthrax or other deadly germs, they said.

"We have not found an indication that anything ever got mixed in the right way to create a weapon of mass destruction," Franks said.

Searchers at the site near Kandahar found medical supplies, laboratory equipment and "a variety of associated supplies" that could be used to make germ weapons, Whitman said. The lab apparently was still under construction when Al Qaeda abandoned it, Whitman said.

Military officials are not sure when Al Qaeda deserted the site, Central Command spokesman Lt. Cmdr. Matt Klee said.

On March 13, forces found the first site that held explosives and equipment to produce more. They also found medical supplies, U.S. Central Command spokesman Cmdr. Dan Keesee said Friday. But no evidence of chemical or biological weapons was found at this site, he said.

Keesee said the factory was found in the embattled Shah-e-Kot valley in eastern Afghanistan, but he did not know if it was located in a cave or buildings.

As many as a dozen ammunition caches in the area — the site of the March 2-18 U.S. offensive Operation Anaconda — were destroyed by Marine Corps helicopter gunships

Despite the end of the operation, U.S. surveillance teams remain in the Shah-e-Kot valley area, a Marine Corps spokesman in Afghanistan said.

U.S. forces have investigated dozens of suspected chemical and biological weapons research sites in Afghanistan.

"Documents recovered from Al Qaeda facilities in Afghanistan show that bin Laden was pursuing a sophisticated biological weapons research program," CIA Director George Tenet told a Senate committee this week.

Despite that, U.S. analysts have concluded that bin Laden had not advanced enough in his effort to create weapons capable of killing large numbers of people.

The Associated Press contributed to this report.