A plainclothes Yonkers police officer was shot while on the job Wednesday afternoon — one week before his planned retirement, law enforcement sources said.

The detective was in critical but stable condition after he was shot once in the abdomen during a confrontation with a suspect inside an Elm Street bodega at 2 p.m., cops said. His shooter was gunned down by an FBI agent, according to officials.

The detective was part of a Westchester County Safe Streets Task Force that was trying to arrest three people as part of an illegal gun investigation.

Several men ran into the store, followed by multiple law enforcement officials in what Yonkers Police Commissioner John Mueller called a “chaotic scene.”

Inside, one suspect tried to push past the detective — who pushed back, Mueller said.

“When our Yonkers detective pushed him back, it appears that he fired one shot at our detective from his pocket, shooting him in the stomach,” Mueller said at a news conference.

“An FBI agent who was part of the Safe Streets Task Force returned fire and the suspect is deceased.”

The detective was taken to Jacobi Hospital in The Bronx, conscious and alert, sources told The Post.

“He has damage to his colon, his intestines and his kidneys and he lost a tremendous amount of blood but thankfully we think he is going to be ok,” Mueller said.

Police arrested the other men involved in the skirmish – which was caught on the bodega’s surveillance camera – and recovered two illegal guns, the commissioner said.

Yonkers Mayor Mike Spano said it was only the third shooting this year in the city of 210,000 residents on the border of the Bronx. He commended the work of the officers.

“We owe them a debt of gratitude but at the end of the day there’s just too much of this happening nationwide and something has to be done,” Spano said.

The wounded officer, who has not been identified, has a brother who is an NYPD cop, according to sources.

He was set to retire around April 28, sources said.