Islamabad, Sep 2 - Pakistani security forces believe that new Taliban commander Hakimullah Mehsud is dead, a media report said Wednesday.

A Pakistani TV news channel quoted intelligence sources as saying that the man died some time back and it was Hakimullah's look-alike brother who spoke to news channels recently.

The brother was summoned from Afghanistan to temporarily head the banned Tehrik-e-Taliban Pakistan, Online news agency reported.

The channel said that security forces were preparing to launch a big offensive against the Taliban in South Waziristan, close to the border with Afghanistan.

Hakimullah Mehsud was appointed the leader of the Pakistani Taliban to succeed Baitullah Mehsud after the latter was killed Aug 5 in a drone attack.

The Pakistani Taliban, an alliance of a dozen militant groups, is blamed for a wave of bomb and suicide attacks across Pakistan, including one that killed former prime minister Benazir Bhutto in December 2007.