Taliban forces in the Afghan cities of Kunduz and Kandahar dug in Thursday for what could be the regime's last conventional battles, even as U.S. Army Gen. Tommy Franks declared that American troops were "tightening the noose" around Taliban leaders and their allies in the Al Qaeda terrorist network.

In Kunduz, the remnants of Taliban forces in northern Afghanistan, including as many as 3,000 zealous foreign fighters, broke off negotiations with opposition soldiers and sought to fortify their defensive positions for battle. In Kandahar, in the south, Taliban troops skirmished with opposition groups and a small number of U.S. Special Forces troops.

But less than a week after the opposition Northern Alliance captured its first major city, Taliban forces continued to dissolve, as some fighters defected, others fled the country and still others sought to blend in with the Afghan population.

In western Afghanistan, more than 100 Taliban soldiers, including at least 19 top leaders, were captured Thursday. The opposition general in charge of the arrests said many of the men had changed their appearance by cutting their hair and shaving their beards.

Although that made positive identification difficult, turncoat Taliban forces tentatively fingered three of the men as the former governor of the Afghan capital, Kabul, and the former governor and the chief of police in Herat, in western Afghanistan.

In the Kandahar area, negotiations apparently were underway between tribal leaders and local Taliban commanders in an effort to get the hard-line regime to give up power without bloodshed.

And in eastern Afghanistan, as the Taliban fled the city of Jalalabad, long-exiled ethnic Pushtun leaders returned to their homeland, driving across the border from Pakistan to take over the governor's palace.

Even as the Taliban appeared to be severely weakened and on the run, supreme leader Mullah Mohammed Omar warned Wednesday of the imminent demolition of the United States.

"The current situation of Afghanistan is related to a big cause--that is, the destruction of America," Omar told BBC radio's Pushtun-language service. "We will see this in a short time."

Asked whether a concrete plan for such destruction existed, Omar replied: "The plan is going ahead, and, God willing, it is being implemented. But it is a huge task which is beyond the will and comprehension of human beings. If God's help is with us, this will happen within a short period of time. Keep in mind this prediction."

Omar had initiated the interview, according to the BBC, which could indicate that he was seeking to bolster the morale of his Pushtun-speaking followers. The Taliban has drawn most of its support from Pushtuns, Afghanistan's dominant ethnic group.

Kandahar, the spiritual birthplace of the Taliban, is in the heavily Pushtun south. Franks said at a Pentagon briefing Thursday that U.S. Special Forces in the Kandahar area have set up roadblocks to help opposition allies fight Taliban forces in the area. U.S. warplanes conducted renewed strikes near the city Thursday.

Opposition sources said that there were growing divisions among Taliban groups in Kandahar and that Northern Alliance forces had surrounded the city and now control most of the province.

Franks, the commander of American military operations in Afghanistan, said U.S. teams had begun supplying arms and other supplies to southern groups.

Deputy Defense Secretary Paul D. Wolfowitz said that after a weeks-long search for southern groups to work with, U.S. military leaders were now reaching a growing number of such groups. They are "frankly coming out of the woodwork rather quickly now," he told reporters.

Franks said that U.S. forces were increasingly focusing their work on their primary mission of finding and destroying the leadership of the Afghan regime and Al Qaeda.

He noted that U.S. warplanes began their air campaign Oct. 7 by hitting major fixed targets, then moved to troops and military vehicles. Now, as those targets are dissolving, U.S. forces are increasingly focusing on trying to hit the leaders--the "alligators," Franks said.

"We're tightening the noose," he said. "It's a matter of time."

U.S. warplanes also continued to aid opposition forces Thursday with strikes on Taliban positions outside Kunduz.