Attack on Police prisoners van in Pakistan

It has been reported that a police van which was carrying prisoners has been attacked. Hand grenade hit the bus. This incident has left seven people injured including four police men. This incident happened on By Pass road in Kot Addu. This is city situated in Pakistan province Punjab South side.
This is adjacent city to Muzaffargarh near Multan.
Pakistan Police should used buses to carry prisoners bomb proof and such attacks should be avoided by terrorists.