When the bodies were taken to the Rajendra Institute of Medical Science here for autopsy, "doctors found a cut mark on the stomach of a dead CRPF man", a police official told IANS.

Suspecting a bomb had been thrust inside the stomach, the doctors called police. A bomb disposal squad defused the explosive.

"This is the first instance in India that a bomb has been found implanted in a body. An x-ray of the body showed a container connected with the cut mark," the police official said.

"The bomb disposal squad had to put water in the body to minimise damage to it. The bomb was removed and later blasted off by the squad."

The weight of the bomb was around two kg and the CRPF trooper in whose stomach it was found has been identified as Babulal Patel.

The police official also said that Maoists had put a pressure bomb under one of the killed CRPF trooper and when villagers lifted the body Tuesday, the bomb exploded and killed two people.

Additional forces sent later Tuesday rescued some of the injured CRPF personnel and also recovered some bodies.

Police said the guerrillas lured the security personnel into a trap near Amuatikar village in Latehar by sending them fake messages.

It led to a gun battle between security forces and Maoists Monday afternoon. It continued till Wednesday.

The guerrillas fired at the unsuspecting security forces from a vantage point.

Maoists are active in 18 of Jharkhand's 24 districts.