The 47-year-old Pakistani has a $5 million dollar bounty on his head and was the target of a US drone strike on Friday, wanted for a string of attacks on Western targets, as well as in Pakistan and neighbouring India.
"There are strong indications that he has been killed in the strike, but we cannot confirm it and we are still trying to confirm it," a senior security official told AFP on condition of anonymity.
Militants on the ground sealed off access to the area of the drone strike and the bodies of those killed were burnt beyond recognition and already buried.
As a result, the official said: "It's impossible for anyone to confirm."
Nine militants were reported killed in the US missile strike at a compound in the Ghwakhwa area of South Waziristan, a stronghold of Al-Qaeda-allied Taliban despite a sweeping Pakistani offensive in 2009.
Officials said Kashmiri had been in the area for several days and that all those killed where fighters in his Harakat-ul-Jihad al-Islam (HuJI) group.
"We have reports about his death and we are trying to confirm these reports," another security official told AFP.
"It is now confirmed that two of his close associates, Amir Hamza and Mohammad Usman, were killed in this drone strike," the official added.