Defiant in the face of stunning setbacks, Taliban supreme leader Mullah Mohammed Omar said in a radio interview Thursday that he'd rather die than join "an evil government" with Afghanistan's former leaders.

"We will not accept a government of wrong-doers. We prefer death than to be a part of an evil government," Mullah Omar told the British Broadcasting Corp., dismissing a U.N. proposal for a multiethnic Afghan government.

Mullah Omar also warned of a larger strategy -- the "destruction of America" -- without specifying what actions may be taken.

The BBC asked the Pashto-language questions by satellite phone through an intermediary who passed them onto the Taliban leader through a hand-held radio. His exact location was unclear, but the private Afghan Islamic Press agency reported earlier Thursday that Omar was in a safe place and in charge of his troops.

Northern alliance advances, backed by U.S.-led bombing, have cost the Taliban their grip on the Afghan capital, Kabul, and deprived them of huge swaths of territory.

Mullah Omar acknowledged that his forces "may have made some mistakes," and was in control of only four or five Afghan provinces.

"But it is not important how many provinces we have under our control," he said. "Once we did not have a single province, and then the time came when we had all the provinces, which we have lost in a week."

He called the Taliban pullback from urban centers part of a larger strategy.

"The current situation in Afghanistan is related to a bigger cause -- that is the destruction of America."

"If God's help is with us, this will happen within a short period of time -- keep in mind this prediction," he said. "The real matter is the extinction of America, and God willing, it will fall to the ground."

"I tell you, keep this in mind. This is my prediction," he warned. "You believe it or not -- it's up to you. But we will have to wait and see."