Pathankot (Punjab), Jan 3 (PTI) A fresh grenade blast ripped through the air force base here this morning claiming the life of an NSG commando, as three other security men succumbed to injuries in a hospital after Saturday's terror attack taking the toll of Indian security personnel to seven

Lt Col Niranjan, a member of the NSG's Bomb Disposal Squad, was killed while he was defusing the grenade at the scene of the terror attack as part of the combing operations that continued through the night. Four other security men were also injured in the blast

Defence sources said Niranjan, a resident of Kerala, was killed while trying to retrieve the grenade from the body of a dead terrorist

Three members of the Defence Security Corps (DSC) succumbed to injuries in the hospital here during the night

Four attackers, a Garud commando and three DSC were killed on Saturday when heavily-armed Pakistani terrorists had attempted to storm the base, triggering a day-long gunbattle at the airbase, barely 35 kms from the Indo-Pak border

Among those battling for their lives in the hospital are 8 DSC personnel?and a Garud commando

Meanwhile, the joint combing operation was still underway, a police official said, adding that the NIA had taken over the probe into the terror incident. Some senior officials of the Punjab Police led by DGP Suresh Arora are also present here.