Al-Qaeda leader Osama bin Laden has vowed to retaliate against "infidel" Pakistani President Pervez Musharraf for the killing of a rebel cleric and a raid on his mosque in July, in a Web audiotape issued on Thursday.
"We in Al-Qaeda organisation call on God to witness that we will retaliate for the blood of Abdul Rashid Ghazi and those with him against Musharraf and those who help him, and for all the pure and innocent blood," said the speaker on the recording who sounded like bin Laden.
"So Pervez, his ministers, his soldiers and those who help him are all accomplices in spilling the blood of Muslims. He who helps him knowingly and willingly is an infidel like him," bin Laden said.
"It is obligatory (under Islam) for Muslims in Pakistan to carry out jihad and fighting to remove Pervez, his government, his army and those who help him," he said.
More than 100 of Ghazi's followers were killed in an assault on the Lal Masjid, a mosque and school complex. The group is sympathetic to the Taliban, who were removed from power in Afghanistan by US-led forces.
Bin Laden's audiotape, issued by Al-Qaeda's media arm As-Sahab, was part of a 23-minute video which carried an English translation of his remarks and showed old footage of him and other figures of his movement. The tape could not be authenticated, but it was posted on the main Islamist Web sites.
Earlier on Thursday, Al-Qaeda's second-in-command Ayman al-Zawahri called on Muslims to fight the United States and its allies around the world, in a new video.
Marking the sixth anniversary of the September 11 attacks, Zawahri said, "Stand, o nation of Islam, under the victorious banner of the Prophet and campaign against the crusader banner of (US President George W) Bush.
"Go forth to the mujahideen, bear them arms, back them, defend them and don't be intimidated by the power of America, for these two blessed attacks have revealed that it is a power of iron and fire, with no faith or morals or principle."
Zawahri, who praised the actions of Al-Qaeda-linked groups fighting in Afghanistan, north Africa, Somalia, Chechnya and Iraq, also called on Pakistanis to avenge the killing of Ghazi.
"Let the Pakistani army know that the killing of Abdul Rashid Ghazi and his students and the demolition of his mosque have soaked the history of the Pakistani army in shame which can only be washed away by retaliation," he said.
Zawahri called on Muslims to restore Al-Andalus -- the Arabic name given to parts of the Iberian peninsula under Muslim rule at various times from the 8th century.
"O our Muslim nation in the Maghreb restoring Al-Andalus (is impossible) without first cleansing the Muslim Maghreb of the children of France and Spain, who have come back again after your fathers and grandfathers sacrificed their blood cheaply in the path of God to expel them," he said.
He also called on Muslims in Sudan to fight a force of African Union and UN peacekeepers set to deploy to the volatile western region of Darfur. He said Sudanese President Omar Hassan Al-Bashir had abandoned Islam.
"The mujahideen sons must organise jihad against the forces invading Darfur as their brothers organised the jihadi resistance in Afghanistan, Iraq and Somalia," he said.
Bin Laden and Zawahri are believed to be hiding in the border area of Afghanistan and Pakistan, a mountainous, inaccessible region that US intelligence has described as a safe haven for Al-Qaeda and their Taliban allies.
The latest audiotape was the third posting featuring a new message from bin Laden to appear this month. The messages were timed to mark the September 11, 2001, attacks on New York and Washington in which almost 3,000 people were killed.
Bin Laden appeared in a video on September 7 in which he said the United States was vulnerable despite its power and said only conversion to Islam would end the conflict.
In an audio tape issued on September 11, bin Laden praised what he called the "19 champions" who carried out the attacks and eulogised one hijacker, who presented his last testament.
The latest Zawahri tape is an 80-minute compilation including old audio clips from bin Laden, comments by Qaeda fighters and clips of Western analysts and officials. Zawahri gives what appears to be a new commentary, explaining how the United States was being defeated by Muslims around the world.
"What they claim is the strongest power in the history of mankind is today being defeated in front of the Muslim vanguard of jihad six years after New York and Washington," said Zawahri, who was wearing a white turban and speaking in front of a packed bookcase. An assault rifle leant against it.
"The coalition of the crusaders has begun to fight the fight of the desperate by increasing its bombing of civilians to discourage them from supporting the Taliban."
The video begins with footage of a cockpit and what analysts said was old audio tape of Mohammed Atta, a leader of the September 11 hijackers, talking to passengers aboard the doomed plane.