A 7-year-old girl was sexually assaulted Saturday in the Upper Marlboro area, the Prince George’s County police said.

They said the girl was approached by someone who sexually assaulted her behind a building and fled. The incident occurred about 3 p.m,. in the Marlton section.

Police said the attacker was described as an older white man with a heavy build. He was bald, with a goatee-style white beard, they said.