NYPD officers salute as an ambulance carrying the body of NYPD officer Brian Moore leaves Jamaica Hospital in New York, May 4, 2015. Moore, 25, was shot in the head on Saturday evening as he tried to question a local man sought on gun charges died on Monday of his wounds, police and City Hall officials said. Moore had been hospitalized in critical condition but died on Monday, the New York Police Department and a City Hall official said. [Photo/Agencies]

NEW YORK - A New York City plainclothes police officer shot in the head over the weekend as he tried to question a local man sought on gun charges died on Monday, police and City Hall officials said.

Officer Brian Moore, 25, was shot on Saturday evening as he and his partner were seated in an unmarked car in a middle-class residential neighborhood of Queens.

He is the first New York City officer killed in the line of duty since two uniformed officers were ambushed in December.

Moore had been hospitalized in critical condition but died on Monday, the New York Police Department and a City Hall official said.

Moore and his partner had been trying to question Demetrius Blackwell, 35, who has an extensive criminal background, after they saw him seeming to adjust an object in his waistband, police said during a weekend news conference.

Blackwell pulled out a gun and fired several times into the vehicle, police said.

New York City Police Officer Brian Moore is seen in an undated picture released by the New York City Police Department. Moore, 25, a plainclothes police officer shot in the head over the weekend, has died of his wounds, local media reported. Moore was shot on Saturday as he and his partner, sitting in an unmarked car in a residential neighborhood of Queens, were trying to question a local man wanted for illegal gun possession. [Photo/Agencies]

He was arrested, charged with first-degree attempted murder, assault and other counts and ordered held without bail. Those charges are likely to be upgraded.

Moore, who came from a family of police officers, joined the force in July 2010, according to Mayor Bill de Blasio. He lived in the suburban Long Island town of Massapequa.

Uniformed officers who lined up outside the hospital in Queens saluted as Moore's body was taken out in an ambulance.

"The people of this great city should take pause this afternoon just to recognize the life of a brave young man who took an oath 4-1/2 years ago to keep the people of this city safe," said Police Chief of Department James O'Neill, who worked with Moore's father on the police force.

"That's what he was doing when he was brutally murdered just a few short days ago," O'Neill said.

The mayor in a statement expressed his sympathies.

"Our hearts are heavy today," he said. "Brian served with distinction and he put his life on the line each day to keep us all safe."

Unlike the shooting in Brooklyn just days before Christmas of Officers Rafael Ramos and Wenjian Liu, who were targeted for their uniforms, Moore was in plainclothes and in an unmarked car, authorities said.

Police said Blackwell was wanted on outstanding charges, including grand larceny, criminal possession of a weapon and menacing. His arrests included two for assaulting police officers, the Daily News reported.

Two New York plainclothes officers were shot while responding to an armed robbery in the Bronx in January and survived their injuries.