CAIRO, Egypt -- An Arab satellite station carried a statement Thursday allegedly from the vanished Taliban leader Mullah Mohammed Omar in which he vows to drive U.S. forces from Afghanistan.

Qatar-based al-Jazeera as well as a prominent Islamic Internet site -- both known for obtaining material linked to Islamic militants -- carried the statement, which was dated to coincide with the Sept. 11 terror attacks anniversary but first appeared Thursday.

It was impossible to verify the statement's authenticity or how the pan-Arab station or Web site obtained it. It was not immediately possible to reach al-Jazeera executives.

"We told our community ... that we are not afraid of Bush's and America's threats," the statement said. "We are continuing jihad against America and all the invaders ... We reassure Muslims everywhere that we are abiding by the pledge, and that victory is coming."

Mullah Omar's radical Taliban government was toppled in U.S-led war on terror following the Sept. 11 attacks. The Taliban had offered sanctuary to Osama bin Laden and his al-Qaida forces.

Mullah Omar, bin Laden and several of their lieutenants disappeared during the fighting in Afghanistan last year and officials in various governments have given conflicting statement on whether they're believed alive or dead.

In the latest such comment, Afghan President Hamid Karzai told ABC's "Good Morning America" program Thursday that he believes bin Laden is probably dead. "The more we not hear of him or see any signal of his whereabouts or survival or otherwise, we are likely to believe he is not alive," Karzai said.