LOWER EAST SIDE -- A cop owes his life to an ammo magazine on his belt that deflected a bullet fired at him in a shootout on the Lower East Side early Monday, police said. Police Officer Thomas Richards and his partner, Thomas Dunne, were shot at as they approached suspect Luis Martinez, 25, in front of a closed drug store at 47 Columbia Street about 1:45 a.m., according to an NYPD account of the shooting. "I heard about 12 at once, then it stopped," said Wilfredo Alvero, 84, of the gunfire. "And then I heard four more. It sounded like an automatic shotgun." Police said one of Martinez's bullets bounced off the spare ammunition magazine at Richard's abdomen, bending the metal casing but saving the officer's life. "Another miracle," said Police Commissioner Ray Kelly in a radio interview with Rep. Peter King, who was hosting John Gambling's program on WOR 710. Kelly added that Richards was lucky to be alive. "An inch either way, and it would have hit his stomach," he said. The gun battle stretched from Columbia Street to Baruch Drive, Kelly said. "Shots are being exchanged as he runs on one side of Baruch Drive and the officers are on the other side," Kelly said at a press briefing later in the morning. Jose Serrano, 66, heard the police officers, amid the gunfire, urging Martinez to stop. "I heard police screaming, 'Stop, stop, stop, stop!" said Jose Serrano, 66, who heard the exchange. "Police were running, yelling, 'Stop shooting!' "I heard about 18 to 20 shots," Serrano added. "It sounded like a big explosion." One of the officers' rounds hit Martinez in the leg, police said. Richards and Dunne followed Martinez's blood trail to 64 Baruch Drive, where he lives, and called Emergency Service Unit cops to capture him. Martinez was tracked down to his apartment and taken into custody. He did not resist arrest, Kelly said. A 9mm Taurus handgun was recovered in a nearby trash compacter, police said. Martinez, whose injury was not life-threatening, was not immediately charged. Kelly said Martinez has prior arrests, but it was not immediately clear for which alleged crimes since they were sealed. The officers were examined at Beth Israel Hospital. Kelly visited them at Police Service Area 4, where the officers are assigned, shortly after the shootout, police said. "It was a very close call for Officer Richards," he said in a statement. "The magazine may have well saved his life." It's the latest in a string of shootings in which officers have survived. Kevin Brennan, 29, was shot in the head while pursuing a suspect in Bushwick, Brooklyn, on Jan. 31; and Kevin Herlihy, 47, was shot in the arm after chasing a suspect into a subway station at 145th Street and St. Nicholas on Feb. 14. Both officers were promoted and honored at One Police Plaza on Friday. "Sometimes these things do come in clusters," Kelly said. "It underscores the nature of the job. Things can be very quiet on the surface and you'll get out and confront someone and things could turn for the worse. "We've been extremely lucky," he added. "But, you know, we don't want our luck to run out."