Muhammad claimed that Taliban elders had held a meeting recently in which it was decided to make him the 'acting' leader of the group.
"I have taken over the leadership of Tehreek-e-Taliban Pakistan. Two days ago our shura held a meeting in which my leadership was endorsed," The Daily Times quoted Muhammad, as saying.
He denied that Mehsud had been killed in a drone attack, but said that the chieftain was ill.
"Baitullah Mehsud is alive, but he is seriously ill. In his absence, I announce, as vice president of the TTP, the takeover of his leadership," Muhammad said.
He also claimed that two other senior Taliban leaders Hakimullah Mehsud and Waliur Rehman, who have been reportedly fighting for the post, have also endorsed his leadership.
Muhammad also announced that Taliban's Swat chapter spokesperson Muslim Khan has been made the Taliban's spokesman, replacing Maulvi Omer, who was arrested recently.