Ayman al-Zawahiri, Al-Qaeda's [Images] deputy leader, has in a new video tape claimed that the outfit's leader Osama bin Laden is alive and leading the holy war against the West.

In the tape, which was partly screened by television channel Al-Jazeera on Wednesday, Zawahiri called upon mujahideen to attack oil installation in Muslim countries since 'most of the revenues from this oil went to the enemies of Islam.

"I call on Muslims everywhere to support their mujahideen brothers in Afghanistan, Iraq and Palestine with money, men and prayer... especially in the countries surrounding these battlefields. America and its crusader allies have not achieved anything. Its forces in the battleground are receiving blows each day," he said.

"All the lies that US President George W Bush [Images] tries to delude the Americans with, saying that he destroyed half, or three quarters of Al-Qaeda are but nonsense merely in his own head," Zawahiri said, adding, "Al Qaeda [Images], thanks to God, is spreading and expanding and strengthening. Prince Sheikh Osama bin Laden, may God protect him, is still leading its jihad (holy war)."

Zawahiri, who is shown wearing a black turban and white robe and speaking against a white background, said the video was to mark the fourth anniversary of the September 11 attacks.

His last appearance was in October, when he urged Muslims in a video broadcast by Al-Jazeera to help Pakistan's earthquake victims even though its government was an "agent" of the United States.

The United States believes that Zawahiri is hiding along with bin Laden and other key Al Qaeda militants in the remote and mountainous border region between Pakistan and Afghanistan.