Ayman al-Zawahiri, 71, who led the al-Qaeda network after the death of founder Osama bin Laden, was born to an Egyptian family in 1951 in Cairo.

His father Mohammed, who died in 1995, was a pharmacology professor at Cairo University, where Zawahiri obtained a master’s degree in surgery.

His grandfather, Rabia al-Zawahiri, was the grand imam of al-Azhar, the centre of Sunni Islamic learning in the Middle East.

According to BBC, Zawahiri became involved in political Islam while still at school and was arrested at the age of 15 for being a member of the outlawed Muslim Brotherhood - Egypt's oldest and largest Islamist organization.

“The current stage demands that we exhaust the enemy until it whines and moans due to economic and military bleeding,” Zawahiri said in a video message.

Zawahiri is considered the main mastermind behind the 9/11 attack that left nearly 3,000 Americans killed.

He had a bounty of $25 million on his head. He became the leader of al-Qaeda after the founder of the network, Osama bin Laden, was killed by the US forces in 2011 in Abbottabad, Pakistan.

“And let us not forget that nineteen Mujahideen, the warriors of Islam, stabbed America in its heart--an injury the like of which American had never tasted before, and today it is making its exit from Afghanistan, broken, defeated, after twenty years of war,” he said in a video message.

Meanwhile, Reuters cited a “senior Taliban leader” saying that “Zawahiri spent most of his time in the mountains of Helmand province's Musa Qala district after the Taliban government was overthrown in 2001 when the United States sent troops to the country.”

“The Islamic Emirate should act responsibly towards the foreign terrorist groups,” said Sayed Sijad Sijadi, a political analyst.

Zawahiri moved to a "very safe place" in Kabul a few months after the Islamic Emirate took control of Afghanistan in August last year, said Reuters, citing a "senior leader" of the Islamic Emirate on Tuesday on condition of anonymity.

Reuters reported that a US official said US officials identified that Zawahiri's family - his wife, his daughter and her children - had relocated to a house in Kabul and subsequently identified Zawahiri at the same location.