Three grenade explosions took place in the winter capital of Jammu on Monday morning, killing one person and injuring 31 others.

Militants hurled the first grenade at the General Bus Stand around 7:32 am, hitting a bus headed for Katra, the base of the Vaishnodevi shrine. Within seconds, two other attacks hit three other buses, police said.

An unidentified person was killed on the spot and 31 people, including two Amarnath pilgrims, were injured, they said adding that three of the wounded persons are in a critical condition.

At least six buses were damaged, four badly, in the attack. Police and Central Reserve Police Force personnel have rushed to the spot and cordoned off the entire area.

However, the extent of the damage and casualties was limited as most of these buses were empty and were awaiting passengers.

Dr S P Vaid, inspector general of police, Jammu range, told rediff.com that militants hurled three powerful hand-grenades in the heavily crowded bus-stand.

"One person was killed on the spot and 31 others have been wounded in the explosions," he said. The injured have been rushed to Jammu's GMC hospital.

Apart from the Amarnath pilgrims, the injured also included two women and a child, two personnel of the Central Industrial Police Force and locals.

"We are investigating these attacks. Three grenades were hurled on the buses, one of them of Vaishnodevi pilgrims," Senior Superintendent of Police, Jammu, Mukesh Singh told PTI on the spot.

Singh, who was monitoring the security situation following the attacks, said, "Grenade pins and other evidence is being searched for to determine if grenades were thrown from the bus stand area or from the road above it."

"Possibility of Hizbul Mujahideen and Lashker-e-Tayiba's involvement in these attacks is there," the police officials said adding that there were also intelligence inputs that militants wanted to disturb the Amarnath Yatra.

The identity of the dead is yet to be known and the body has been kept at the mortuary of the GMC hospital. Five persons have been discharged after being administered first aid while 26 are undergoing treatment at the hospital, police said, adding that militants may have wanted to target the Vaishnodevi pilgrims as the bus they hit was Katra-bound.

The two injured Amarnath pilgrims have been identified as Rekha [Images] Devi from Ahmedabad and Babli Paswan from Bihar, police said. Security has been beefed up in and around the city in the wake of the grenade attacks and security of the MAM stadium housing the Amarnath pilgrims has also been stepped up.

People and vehicles were being thoroughly searched and "efforts made to track down the militants responsible for the attack", police said. A high level meeting of police officials was held in the city to review security situation in Jammu, where the Amarnath yatra and BJP's satyagraha are on, they said.

With PTI inputs