A man was seriously injured in a Frankford shooting in which he was approached from behind and then shot, Philadelphia police said.

The victim, 31, and his girlfriend were outside on the 4600 block of Frankford Avenue just after 9 p.m. when two men walked up behind him — and one began to shoot, police said.

The victim was shot three times in the left leg and once in the abdomen by a heavyset man in a black ski mask and a black hoodie, police said. Police rushed him to Temple University Hospital, where he was listed in critical condition.

No weapon had been recovered, and no arrests had been made Sunday night. Police did not have a description of the second man involved in the shooting.