ISLAMABAD — Security forces captured the Pakistani Taliban's top spokesman, and he acknowledged the death of the group's leader in a recent U.S. missile strike, officials said Tuesday.

U.S. and Pakistani officials have said they were almost certain that the chief, Baitullah Mehsud, had been killed in the Aug. 5 strike, but at least three Taliban operatives, including the detainee, Maulvi Umar, had called media organizations following the attack to say he was still alive.

Umar's comments were relayed by an intelligence official who took part in the questioning.

The spokesman's capture was the second arrest of a prominent Taliban figure in 24 hours, dealing another blow to the network blamed for scores of bloody attacks on Western and government targets gnawing at the stability of the nuclear-armed country.

As the official spokesman for Tehrik-e-Taliban Pakistan, the umbrella organization formed in 2007 for various regional and tribal militant movements, Umar frequently called journalists to claim responsibility for terrorist attacks in Pakistan.

As well as being the movement's mouthpiece, Umar was an influential aide to Mehsud and ranking member of the Taliban.

Umar was captured along with two associates in a village in the Mohmand tribal region Monday night while he was traveling in a car to South Waziristan, a Taliban stronghold, said Javed Khan, a local government administrator.