In the first of the Thursday incidents, off-duty officer Juan Pichardo, 34, suffered a leg wound shortly before 6:30 p.m. while fighting off robbers at his car dealership in the Bronx, the New York Daily News reported. Four suspects were later arrested.
An hour later in Brooklyn, two officers and a civilian passenger were wounded in a gunbattle on a subway train. The officers, Michael Levay and Lukasz Kozicki, killed the gunman, the Daily News said.
All four wounded men were expected to survive, the newspaper said.
"As both of these incidents illustrate, the historic crime reductions that New Yorkers enjoy come at a price," Police Commissioner Raymond Kelly said at a news conference.
"A dozen police officers were shot last year. And now three more, in the first three days of the new year, so thank God ... all of these officers will recover."
In the train shooting, the officers had confronted the man after spotting him walking between cars, police said. Sources told the newspaper that when the officers tried to remove the man from the train, he drew a gun and fired at least four times, hitting Kozicki three times in his upper thighs and groin. Levay was grazed in the back by a bullet and the civilian passenger was grazed in the leg.