Separatist guerrillas Thursday shot at a private security guard posted at a hospital here, an official said, adding his condition was critical.Nazir Ahmad was working as a security guard at the Shri Maharaja Hari Singh (SMHS) hospital here when he was shot at by militants. He was critically injured. "Militants fired at the ex-serviceman from close range," a police official told IANS.Ahmad belongs to the Kupwara district in north Kashmir and was working with a private agency in Kaka Sarai in the city.Panic gripped the otherwise busy area when shots were heard as traffic came to a halt.