In a recording released Thursday, al Qaeda leader Osama bin Laden declared war on Pakistan President Gen. Pervez Musharraf, calling on Pakistanis to rebel against the government.
Bin Laden, his voice heard on a video showing previously released footage of the terrorist leader, says the Pakistani military's storming of the Red Mosque in Islamabad in June shows Musharraf's willingness to bend to the will of the U.S.
The move "demonstrated Musharraf's insistence on continuing his loyalty, submissiveness and aid to America against the Muslims ... and makes armed rebellion against him and removing him obligatory," bin Laden says.
"So when the capability is there, it is obligatory to rebel against the apostate ruler, as is the case now."
The statements were taken from a transcript released by Laura Mansfield, a U.S. terrorism expert who monitors militant message traffic, and cited by The Associated Press.
The Pakistan military responded soon after the video was released.
"We have the aim and objective, as our national duty, to eliminate terrorists and eradicate extremism. The Pakistan army will continue to carry out its role against terrorists wherever they are found, whether in the tribal areas (of northwest Pakistan) or elsewhere," said Maj. Gen. Waheed Arshad, a Pakistani army spokesperson.
"Such threats issued through videos or in any other way cannot deter us from fulfilling our national duty," he said.
Thursday's video was posted on an Islamic militant website.
Musharraf has recently vowed to eradicate the presence of foreign terrorists in Pakistan's lawless tribal areas.
Alan Bell, president of Globe Risk Holdings, told CTV's Canada AM the video release is probably linked to Musharraf's statements.
"I think this is really worrying al Qaeda and Osama bin Laden in particular," Bell said. He added that the recording serves as further evidence that bin Laden is still alive and able to respond to ongoing events.
Bin Laden and al-Zawahri are thought to be hiding in the lawless Pakistan-Afghanistan border region, where many analysts believe they have rebuilt al Qaeda's core leadership.
Bell said this is one of the last safe havens for al Qaeda fugitives, and Musharraf's pledge to eradicate it could be worrying the militants.
The Thursday message came as al Qaeda released a new tape of Ayman al-Zawahri, bin Laden's second in command.
In the 80-minute video, al-Zawahri claims the U.S. is being beaten in Iraq and Afghanistan, and al Qaeda members vow further clashes in Afghanistan, North Africa and Sudan's troubled Darfur region.
The video is done in documentary style, intersplicing al-Zawahri's speech with footage from the Sept. 11 attacks, interviews with experts and officials taken from Western and Arab television stations, and old footage and audiotapes of bin Laden.
He begins by condemning the Pakistani military's assault on the Red Mosque in Islamabad in June, then pays tribute to Abdul Rashid Ghazi, one of the militants' leaders who was killed in the fighting.
The siege "revealed the extent of the despicableness, lowliness and treason of Musharraf and his forces, who don't deserve the honour of defending Pakistan, because Pakistan is a Muslim land, whereas the forces of Musharraf are hunting dogs under (President) Bush's crucifix," al-Zawahri said.
"Let the Pakistani army know that the killing of Abdul Rashid Ghazi and his male and female students ... has soaked the history of the Pakistan army in shame and despicableness which can only (be) washed away by retaliation."
Al-Zawahri calls for attacks on French and Spanish interests in North Africa, as well as against United Nations and African peacekeepers expected to deploy to Darfur.
The video also shows footage of Mustafa Abu al-Yazeed, al Qaeda's leader in Afghanistan, meeting with a top Taliban commander.
The two groups, according to statements in the video from al-Yazeed and Taliban boss Dadullah Mansoor, are working more closely together.
Al Qaeda began a stepped-up propaganda campaign around the anniversary of the Sept. 11, 2001 attacks against the World Trade Center and the Pentagon. Bin Laden released two messages earlier this month -- including his first new appearance in a video in nearly three years.
With files from The Associated Press