Police shot an armed man Saturday night after he ran from a parked minivan in Philadelphia's Olney section and pointed a gun at one of two officers who chased him, police said.

The officers, while on patrol, noticed the vehicle illegally parked in a crosswalk at North Fourth Street and Lindley Avenue shortly before 6 p.m., police said. When officers approached, a side door of the van slid open and one man ran out with "an object in his hand," police said.

After a brief chase, one officer caught up with the man and pushed him into a parked vehicle, causing him to stumble. When he regained his footing and turned around, officers saw him holding a gun, police said. He then ran toward one of the officers, prompting his partner to shoot, hitting the man in the back, police said.

The man, described only as 20, was taken to Einstein Medical Center, where he was in critical condition Saturday night.

A weapon was recovered at the scene and an unspecified amount of marijuana was found in the minivan, police said.

The officers have not been identified. The one who fired will be put on administrative duty pending the outcome of an investigation.

Photographer Joe Kaczmarek contributed to this article.