Four police personnel were injured when an armed group detonated an improvised explosive device targeting a patrol van at Surunga Municipality-5 in Saptari on Saturday night. 

The police van was ambushed at Shreepur.  The injured officers were admitted to a hospital in Lahan. 

Meanwhile, an obscure outfit that calls itself Pragatishil Tarai Mukti Morcha claimed responsibility for the attack by issuing a statement on Sunday.