Pakistan troops have surrounded Ayman al-Zawahiri, Al-Qaeda leader Osama bin Laden's second-in-command, in South Waziristan, near the Afghan border, according to reports.
President Pervez Musharraf told CNN it might be a 'high-value target'. But "I can't say who", he added.
The development came as Pakistani troops launched a new ground and aerial offensive against Al-Qaeda and Taliban terrorists in the region, where 40 people, including 16 paramilitary personnel, were killed in fighting on March 16.
The troops used helicopter gunships in the operation, defence ministry spokesman Major General Shoukat Sultan said in Islamabad.
Prior to the operation, he said, the authorities asked locals to leave the area.
"Thursday's operation is continuation of the operation first launched on March 16th," he said.
"The militants and their supporters showed stiff resistance on first day of operation."
With Inputs from PTI
EXTERNAL LINKSEgyptian physician with a $5 million price on his head
Zawahiri's Whereabouts
Ayman Zawahiri: Bio of al-Qaida's #2
Ayman Zawahiri: The ideologist
Ayman Al-Zawahiri: attention turns to the other prime suspect
Ayman al-Zawahiri, Psychiatrist, the leader of the Jihad Organization
The Operations Man: Ayman al-Zawahiri
Al-Qaeda terrorist network and Taliban intact: Zawahiri
Behind Mubarak
More than a deputy, this man could be Bin Laden's inspiration
"Ayman al-Zawahiri's Russian Adventure"
FBI notice on Zawahiri
More from rediff