(CNN) -- The man described by counterterrorism officials as al Qaeda's "military brain," Ilyas Kashmiri, was killed in a drone strike Friday night in Pakistan, a spokesman for his group, the jihadist Harakat-ul-Jihad-Islami, said.
Pakistani and U.S. officials, however, said they have not confirmed Kashmiri's death.
Kashmiri was killed, along with some aides, in a strike at 11:15 p.m., spokesman Abu Hanzla Kashar said.
"The oppressor U.S. is our only target and, God willing, we will take revenge on the U.S. soon with full force," he said.
A senior Pakistani military official said that in all, nine were killed by the drone strike. The official reiterated that they had not confirmed Kashmiri's demise.
Kashmiri, who was known to operate in North Waziristan, had moved to South Waziristan and was seen at the site of the attack on Friday, the official said.
If confirmed, his death would be the first major kill or capture since Osama Bin Laden, and the highest profile drone target since Beitullah Mehsud in 2009.
It could also be seen as an embarrassment for Pakistanis, who have twice in just over one month, had a major al Qaeda figure killed on their territory without their participation.
U.S. drones now operate entirely autonomously in Pakistan, a Pakistani intelligence source has told CNN. Whereas before the United States cooperated with Pakistan and used their intelligence, today, the Americans have an intelligence network that allows them to go after terrorists unilaterally.
Kashmiri, a veteran jihadist, is considered one of the most dangerous men in the world by counterterrorism officials on three continents.
He was commander of "Brigade 313" of Harakat-ul-Jihad-Islami, which has formed a close relationship with al Qaeda.
Kashmiri is also said to have ties with David Coleman Headley, the U.S. citizen who confessed to helping scout
targets for the Mumbai attack in November 2008. After his arrest, Headley said he had twice met Kashmiri.
During questioning by India's National Intelligence Agency, which was given access to him in Chicago, Illinois, in June 2010, Headley said he'd been taken to Pakistan's tribal territories to meet Kashmiri early in 2009.
A copy of the interrogation obtained by CNN reveals that Kashmiri sent Headley on another trip to survey targets in India. One place he said he videotaped was a bakery that was later attacked in Pune in February 2010.
Kashmiri in his early years fought the Indians in the disputed territory of Kashmir and the Russians in Afghanistan, where he lost an eye.
He famously escaped from an Indian jail and went to fight with a unit of Pakistan's special forces. Eventually, he fell out with his sponsors in the Pakistani military, and moved his operations to North Waziristan.
At one point, he was arrested in connection with an attempt to assassinate Pakistan's president, Gen. Pervez Musharraf, in 2003. For reasons unknown, Kashmiri was released a short time later.
CNN's Nasir Habib, Nick Paton Walsh and Tim Lister contributed to this report.