A convenience store clerk in Ingram turned the tables on a knife-carrying robber yesterday, shooting and seriously wounding the would-be thief, police said.

Ingram Police Chief John Doherty said the clerk may have fired at the robber inside and then outside the 7-Eleven store at 10 W. Prospect Ave.

"He shot the robber several times. I'm not sure how many," Chief Doherty said in an interview.

The gunfire began in the store about 4:30 a.m. and then apparently continued outside, he said.

Chief Doherty declined to identify either the clerk or the robber. He said the would-be thief is 20 years old and the clerk is in his mid-20s.

Emergency crews transported the robber to Allegheny General Hospital, where he underwent surgery, Chief Doherty said.

He said the clerk may have had a less serious injury.

"I believe the clerk was cut," the chief said.

Chief Doherty said the preliminary investigation showed that the clerk had a permit to carry a firearm. He said he knew this particular clerk because he had been robbed previously and Ingram police investigated that case.

7-Eleven has had a no-weapons policy for store employees since the 1970s. Chief Doherty said he did not know whether the Ingram clerk violated a corporate rule by carrying his gun.

An employee at the 7-Eleven store in Ingram referred questions to a manager, who was not in yesterday.

Corporate offices of the Dallas-based chain were closed yesterday because of the Christmas holiday. But 7-Eleven executives at the corporate level have said that one weapon carried by a store employee was one too many.

The 7-Eleven chain, with more than 32,000 stores worldwide, has instead tried to deter robberies by keeping only small amounts of cash in registers and by using security cameras.

Allegheny County police will be the lead agency in the Ingram case. They will decide what charges to file, Chief Doherty said.