A bomb blast on a passenger train has killed at least three people and wounded 20 others in central Pakistan.

The attack in the central town of Rajanpur, Punjab province on Friday derailed eight wagons of the train, which was travelling from Peshawar to Karachi.

Speaking to the AFP news agency, senior police official Zahid Mehmood Gondal said: "At least three people were killed and 20 others wounded when a bomb exploded in one of the compartments of [the] Khushhal Khan Khattak express".

There was no immediate claim of responsibility for the attack, he added. 

Since July 2007, Pakistan has been gripped by a local Taliban-led insurgency, concentrated largely in the northwest.

The government says more than 40,000 people have been killed in violence since 2001, when Pakistan allied itself with the US-led "war on terror".

Source: AFP