A convenience store employee suffered head injuries during a robbery in La Mesa, police reported Saturday.

The employee of a 7-Eleven store at 8300 Parkway Drive told police he noticed a man take two 18 packs of beer and head for the store's exit around 9:40 p.m. Friday.

The employee followed the man outside to confront him, but when the robber turned around he dropped the beer and punched the employee twice in the head, La Mesa police Chief Alan Lanning said.

Lanning said that when three to five men in their 20s saw the fight, they pulled the robber away from the employee; the robber ran north on Jackson Drive.

Two people who were with the robber ran into the night, and the rest left in an off-white or tan mid-1980s four door Buick sedan with a license plate of AGC707, Lanning said.

Paramedics transported the employee to the hospital for treatment of a 2-inch laceration and a contusion on his head, Lanning said.

He described the robber as man in his early 20s, about 5 feet 10inches tall, with thin build and a shaved head.

Anyone with information should call the La Mesa Police Department at 619-667-1400.