New York, NY - Just a few days after a Long Island police officer was killed in the line of duty, an NYPD officer is shot in the chest after breaking up a mugging in The Bronx.  Despite his serious injury, he still managed to chase down and kill one of the robbers, officials said.

Ivan Marcano, 27, applied pressure to the gunshot wound on his chest while returning fire, Police Commissioner Ray Kelly said.

The bullet that struck Marcano grazed his left arm and entered his chest—just missing his heart—and fractured a rib. He was in stable condition last night at Bronx Lebanon Hospital, surrounded by family.

He is the 12th NYPD cop wounded this year.

Mayor Bloomberg met with Marcano—a transit officer in The Bronx—and said, "He's a very lucky guy and he knows it."

The drama began at about 6:40 p.m. when Marcano was riding with his girlfriend and she noticed two thugs robbing a man of $80 on Harrison Avenue in University Heights, authorities said.

"Give me the money out your pockets!" one of the brutes barked, according to a witness.

Another mugger pistol-whipped the victim and shouted, "Give me whatever you got!" said the ­witness.

Marcano, who has been on the force since 2007, jumped out of his white Infiniti, flashed his badge and said he was a cop.

At least one of the suspects fired at him.

After Marcano was hit, the two suspects hopped into a white Ford Mustang, with a driver waiting for them, and sped off.

Marcano got back into his car and his girlfriend frantically drove toward the hospital.

The suspects happened to be in front of themand rolled into the intersection, striking a livery cab.

The cab struck another car and went up onto a sidewalk.

As the three suspects ran from the Mustang, Marcano recognized them and pursued them on foot.

While taking cover and yelling to passers-by to "Get down!" Marcano fired at the muggers, Kelly said.

"In a remarkable display of marksmanship and cool under fire, Officer Marcano fired, striking one of the suspects in the head," Kelly said.

A witness said he heard at least 10 shots. "It happened quickly. When I turned around, there was a dead guy lying on the ground under the car," said Emilio Acevedo, 17.

Marcano then chased after another suspect, but was unable to catch him. The cop finally hopped into an ambulance and was rushed to the hospital.