A 35-year-old security guard was shot and injured by three assailants when he resisted their robbery attempt at a scrap warehouse here, said police on Sunday. Ashok, a former army man hailing from Jhajhar in Haryana, was attacked by the unidentified robbers at a warehouse of scrap material in west Delhi’s Mundka area Saturday night, police said. He received bullet injury in the abdomen and was undergoing treatment, police said.