Al-Zawahri tape probably genuine

The US and Pakistan have launched co-ordinated raids against al-Qaeda

An audio tape aired on Arab television station al-Jazeera on Thursday is "likely" to be that of Osama Bin Laden's deputy, US officials say.

But the CIA said it was not clear when the tape - said to have been made by Ayman al-Zawahri - had been recorded.

In it the speaker urges Pakistanis to overthrow President Pervez Musharraf.

Last week, Pakistan's army launched a big operation on the Afghan border targeting a "high-value target" - suspected to have been Mr Zawahri.

'No orders'

The taped message called on "Muslims in Pakistan to get rid of their government which is working for Americans".

In particular, it urged soldiers in Pakistan's army to "disobey orders" and carry out a coup d'etat against Gen Musharraf.

Musharraf seeks to stab the Islamic resistance in Afghanistan in the back Ayman al-Zawahri Profile: Ayman al-Zawahri Excerpts of 'al-Qaeda tape'

"After conducting a technical analysis, the CIA has assessed that the voice on the tape that was aired yesterday on al-Jazeera television is likely that of Ayman al-Zawahri," a CIA official said.

The message refers to Pakistani operations on the border with Afghanistan - seeming to suggest it was recent recording says the BBC's Adam Brookes in Washington.

But the CIA said such operations had been going on for a while - so it was not clear when the message was taped, our correspondent says.

Before the announcement, the Pakistani government condemned the message.

"Pakistan does not take orders from anybody," said Information Minister Sheikh Rashid Ahmed.

"Ayman al-Zawahri has tried to damage both Islam and Pakistan by making this baseless statement," Mr Ahmed said.

Pakistan offensive

Pakistan's army has been waging an offensive along the country's western border with Afghanistan - traditionally a stronghold of deeply conservative Pashtun tribes.

The intensity of the fighting in the South Waziristan region prompted speculation that the tribesmen were protecting a "high-value" al-Qaeda target.

But with no sign of Mr Zawahri among those killed or captured, Pakistani officials later conceded the claim may just have been "guesswork".

Other reports suggested Mr Zawahri - if indeed he was there - may have fled the fighting through a network of underground tunnels.

On Friday, Pakistan announced it was sending reinforcements to its massive operation which is being co-ordinated with a US military sweep in neighbouring Afghanistan. The US is also sending 2,000 marines to boost up its operation.