Srinagar: Three army commandos, including two Captains, and a militant were killed on Sunday in the fierce gunfight with a group of terrorists holed up inside a government building on the outskirts of Srinagar, raising the toll to seven in the encounter that began on Saturday afternoon. The multi-storied building of Entrepreneurship Development Institute (EDI) building in Pampore caught fire on Sunday afternoon as the encounter between army and the heavily-armed terrorists, suspected to be 3-4 in number, continued till late tonight on the second day. Through the day, the terrorists kept on firing and throwing grenades on the security forces who have surrounded the building and making attempts to storm it. Army lost Captain Pawan Kumar, Captain Tushar Mahajan and jawan Om Prakash, all of the elite Para commando units, in the gunbattle on Sunday. The army succeeded in eliminating one of the terrorists by Sunday evening, an official said. Captain Pawan Kumar, who hailed from Haryana's Jind, sustained grievous injuries in militant firing as security forces tried to make their way into the building in the wee hours on Sunday, an army official said. He succumbed to injuries later. Captain Tushar Mahajan from Udhampur was also injured in the encounter and succumbed to injuries later at hospital. As the security forces exchanged heavy gunfire with the holed up militants, another soldier from the Para unit, Om Prakash, was injured and taken to 92 Base Hospital of the Army at Badamibagh Cantonment where he succumbed. The terrorists have been holed up in the building since Saturday afternoon after they attacked a CRPF convoy, killing two jawans and a civilian and injuring nine other jawans. Nearly 100 civilians -- staff and students of EDI -- were evacuated to safety by the security forces from the building, a police official said. He said the operation might be prolonged as militants seem to be heavily armed. The open structure of the building where the militants are hiding also poses a difficulty to the security forces in advancing towards it, he added.