Armed with AK-47 rifles and grenades, a group of four militants attacked the CRPF troops centre at around 2.20 am, a CRPF spokesperson said.

One of the four militants entered the camp hurling grenades and firing indiscriminately, he said, adding the rest of the ultras stayed behind and escaped after some time.

Security personnel and police patrolling the area intercepted the attackers leading to a fierce gun battle in which seven CRPF personnel and a civilian were killed.

The spokesperson said the militant, who entered the camp, is believed to be inside the premises and efforts are on to locate him.

Five personnel, including three CRPF jawans and one each from state police and home guards, have been injured in the gun battle.

The civilian killed appeared to be a rickshaw puller, Senior Superintendent of Police Sanjiv Gupta said.

Giving details about the incident, Additional Director General (Law and Order) Brij Lal said the militants opened fire killing two CRPF men and hurled grenades while entering the group centre.

In the firing inside the premises, five CRPF jawans, who were sleeping, were killed, he said.

However, gate number two, where a large number of arms and ammunition were kept, had not been attacked, he said, adding the area has been cordoned off.