Police are investigating after two girls spotted a man with his pants around his knees masturbating beside a tree along a Dartmouth street.

Halifax Regional Police say the indecent act happened on Monday around 3 p.m. near the corner of Waverley Road and Craigburn Drive.

Police say two 13-year-old girls saw the man as they walked home from their school bus stop.

The man did not approach the girls or say anything to them.

The teens ran away and told their parents. Police were contacted Wednesday.

Police say the suspect in a white man in his 20s, with a muscular build and short dark hair. He was shirtless and was wearing grey shiny sweat pants.