Osama bin Laden has called on Pakistani Muslims to join Afghan fighters in fighting American "crusaders" in a new Internet statement purported to be from the al-Qaeda leader.
The authenticity of the statement, which appeared on a website known as a clearing house for militant Muslim comment, could not be verified.
"We urge our Muslim brothers in Pakistan to use all their capabilities and whatever they possess to prevent the American crusader's troops from invading Pakistan and Afghanistan," said the statement, signed: "your brother in Islam, Osama bin Laden".
The statement also referred to deaths during an anti-US protest in Karachi, Pakistan's biggest city.
Although violent protests have occurred elsewhere in Pakistan, there have been no reports of a demonstration in Karachi that resulted in fatal clashes.
The Arabic station Al-Jazeera received and aired on October 29th the latest bin Laden video, in which he directly acknowledged for the first time that he ordered the September 11th attacks and criticised President George Bush.
Bin Laden is believed to be hiding in a mountainous Afghan-Pakistani border area, having fled there after a US invasion toppled his Taliban hosts.