SAN ANTONIO -- An officer with the San Antonio Police Department shot a knife-wielding man who police officials said tried to attack the officer Thursday morning.

The man in his late 20s was listed in critical condition at Brooke Army Medical Center.

SAPD Chief Bill McManus said that Officers Scott Ambrose and Emanuel Keith responded to a call about a man harassing customers at a Valero store at 2903 E. Southcross Boulevard at 5 a.m.

When Ambrose arrived at the store, the man pulled out a knife and then fled on foot, police officials said.

Ambrose chased the man on foot and that was when Keith arrived to assist, police officials said.

The man then tried to climb a fence in the 2700 block of Bill Miller Lane, where the officers used a Taser gun and an extendable nightclub in an effort to subdue the man, police officials said.

Seconds later, the man then tried to attack Keith with the knife, police officials said.

"The suspect closed in on one officer, the officer who Tased him," McManus said. "At that point, the officer shot the suspect in the chest."

Witnessed told KSAT 12 News that they heard as many as five gunshots but police officials weren't able to immediately verify that.

Keith, who is a 12-year veteran of the force, has been placed on administrative duty pending an investigation.