Terry Tang, Associated Press
Chandler police spokesman Seth Tyler stands behind crime tape at the scene of a police involved shooting at a Walmart store on Saturday, April 23, 2016 in Chandler, Ariz. Authorities in a Phoenix suburb say two officers have been shot and a suspect is dead. Tyler says both officers are hospitalized in stable condition.

CHANDLER, Ariz. — Two officers are in stable condition, with one requiring surgery, and the suspect is dead following a shooting Saturday at a Walmart in suburban Phoenix, authorities said.

Mitchell Oakley, 24, was killed after opening fire at officers who were responding to a call about a trespasser, Chandler police said. Police were called around 6:30 a.m. about a trespasser at the store, Chandler police spokesman Seth Tyler said.

The officers encountered Oakley at the front of the store, just past the greeters' area.

According to witnesses, the first officer entered the store and was fired upon immediately by the suspect, Tyler said.

The second officer, who was in close proximity, was also shot but was able to return fire. It is uncertain if the first officer discharged his weapon. Both were wearing bulletproof vests.

The names of the officers have not been released.

"I guess you can call it what you want. It sounds like an ambush to me," Tyler said.

The Walmart Supercenter was open for business at the time but is now closed. It is unknown how many people were in the store at the time.

Cynthia Ayala was on the other side of the store in a dressing room when she heard the gunfire but didn't at first realize what she heard.

"I thought it was like pallets falling. I never thought it would be gunshots," Ayala said.

She said the shots came one after another and then it became apparent they were bullets.

"I was just really scared as to where they would fall," Ayala said.

She came out of the dressing room when things calmed down. She said employees then escorted her and other shoppers to the store's garden center.

Oakley was a transient but had family in the Chandler area, police aid.