Six killed in Pak blast

It could not immediately be ascertained why the bus,which was carrying civilians,was targeted.

In the past few weeks,militants and suicide bombers have targeted several security facilities,including the army8217;s fortified headquarters in Rawalpindi,Federal Investigation Agency office and police training centres in Lahore and the ISI8217;s provincial headquarters in Peshawar.

Dozens have died in these attacks.

The Taliban have claimed responsibility for many of the attacks on the security forces,which began after the army launched operations against militants in South Waziristan tribal region in October.