Halifax Police are investigating an attempted armed robbery in downtown Halifax last night. Shortly before 9pm an 18-year-old man withdrew money from an ATM machine on Spring Garden Road. While walking to his home on Lucknow Street he was approached by a man who demanded his wallet. When he hesitated the suspect pulled knife. The victim pushed the man away and the suspect dropped the knife before pushing the victim to the ground and punching him in the head. The victim was able to grab the knife and yell for help and the suspect fled. Nothing was taken during the altercation. The suspect is described as a clean shaven white man, roughly 5-foot-10, wearing a grey hooded sweater.