A woman was attacked by an armed robber early Tuesday in the Pilsen neighborhood on the South Side.

The 24-year-old was walking down an alley when a male she didn’t know took out a handgun and announced a robbery about 12:30 a.m. in the 1000 block of West 18th Place, according to Chicago police.

He stole her cell phone and wallet and then ran away heading south, police said.

No injuries were reported.

Area Central detectives were investigating.