Three civilians, an army trooper, and a militant were killed in an ongoing fierce gunbattle between militants and surrounding security forces in Jammu, which is in the throes of a 60-day long violent Amarnath land row agitation.

Police said a group of militants came to Bantallab locality in an autorickshaw on Wednesday morning and started firing indiscriminately resulting in the death of three civilians.

"The area was immediately cordoned off and an operation was launched to flush out the militants who are holed up in a house and are engaging the security forces in a sustained encounter. Three civilians, one junior commissioned officer and a militant have been killed in the encounter so far," a senior police officer said.

The security agencies had on Monday said that a group of heavily armed militants had crossed into this side of the international border at Kanachak after cutting the barbed wire fence.

An alert had been sounded in Jammu city and a manhunt launched to trace the group that sneaked in.

"The entire area has now been surrounded. Intermittent firing exchanges are continuing in the Bantallab area," the officer said.

The militants have taken eight people, including four children, three women and a man as hostage.