NEW YORK -- A gunman rampaged through a strip of restaurants and bars in a trendy Manhattan neighborhood, killing two unarmed volunteer police officers and a pizzeria employee, the mayor said.

Video: NYC Shooting Rampage

Regular police officers then shot and killed gunman David Gavin, who had a bag with a fake beard, two guns and 100 rounds of ammunition, Mayor Michael Bloomberg said early Thursday.

A neighborhood resident, Tina Lourenco, said she saw the gunman and recognized him as a former employee of the pizzeria.

"Tonight was a horrible night for the New York Police Department and for our city," Bloomberg said. "Two men who volunteered their time to make our city the safest big city in America lost their lives helping to keep it exactly that way."

The bedlam began around 9 p.m. Wednesday, when Gavin, 32, went into De Marco's Pizzeria in Greenwich Village, the mayor said. Gavin asked for a menu and then shot an employee 15 times in the back, Bloomberg said. Police identified the employee as Alfredo Romaro, 35.

Gavin fled, and nearby police who had heard the shots radioed information about the gunman. Auxiliary Officers Nicholas Todd Pekearo and Eugene Marshalik, on their regular patrol nearby, came toward Gavin, who crossed the street and fired at them. Auxiliary officers are civilian volunteers who wear uniforms, are unarmed and help patrol streets.

"(Gavin) literally crossed the street ... to kill them in cold blood," Bloomberg said of the gunman.

Gavin then exchanged gunfire with uniformed officers, who shot him, the mayor said. Several uniformed officers suffered minor injuries. Authorities recovered the 9mm semiautomatic pistol Gavin fired, plus a .380-caliber semiautomatic handgun in a bag with the ammunition, Police Commissioner Raymond Kelly said. Gavin shot at least 23 rounds.

"He appeared to be ready to take even more lives," said Kelly.

Pekearo, 28, was a writer with a book scheduled to be published soon, the mayor said. Marshalik, 19, a student at nearby New York University, had immigrated from Russia, Bloomberg said. The mayor said Marshalik hoped eventually to join the police force.

Marshalik was an undergraduate student in NYU's College of Arts and Science, said university spokesman John Beckman.

"This is terrible and shocking news -- shocking because our neighborhood is customarily such a safe one, and terrible because one of our students was killed performing the noblest kind of community service," Beckman said.

Residents of the area said they too were shocked by the violence.

"It's very not typical of the area," said Amy Stoyko, who lives on a block of Bleecker Street that was still cordoned off Thursday morning.

Romana Raffetto, who owns a pasta shop next door to the pizzeria and lives above the shop, said she did not realize what was happening when the shots rang out Wednesday night.

"I'm so dumb: I heard shooting but I didn't pay attention," she said. "I live here since 1960 and you always hear sirens."

Nearby, someone had taped a sign to a lamppost along with pink silk flowers. It read: "Rest in peace, our beloved auxiliaries."

City officials said the two auxiliary officers would get full police honors at their funerals.

Marshalik and Pekearo were the first New York City auxiliary police officers to die in the line of duty since 1993, according to the mayor. Only five other auxiliary officers have died in the line of duty in the city's history.

There are nearly 4,500 auxiliary officers in New York, and their uniforms are nearly identical to those of police officers. They do not carry weapons, and they are not issued bulletproof vests. The mayor said one of the officers killed was wearing a vest, but it did not make any difference in this instance.

Kelly said auxiliary officers are the "eyes and ears" of the police force.

"Day in and day out, they sacrifice their free time and energy for the people of our city," Kelly said.

Authorities were unsure whether the gunman fired because the volunteer officers looked like uniformed police.

"Inexplicable would be the only word I would use ... There's nothing you can say," Bloomberg said.

Kelly said the auxiliary officers aren't required to respond to calls, but that the victims were likely just trying to help out.

A worker in a nearby restaurant, Nikola Simic, said he saw police officers swarm toward the middle of the street where the auxiliary officers were slain.

"Then we heard a shooting that was like a good five minutes," Simic said.

Josh Drimmer was inside a bar at the time of the shooting.

"Hearing that many shots in a row," he said, "it was war. It felt like that for a hot second."

The shootings occurred near NYU's downtown campus, close to Washington Square Park and near several famous bars and restaurants, including Cafe Wha?, where Bob Dylan used to perform.

The shootings came after three city police officers were injured in separate incidents within the previous day.

A few hours earlier, a police officer wrestled with an illegal Manhattan street vendor before they crashed through a storefront window. The officer received seven stitches to his right hand and 10 stitches to his chest. The vendor, who was held, suffered minor cuts.

Two other officers were injured Tuesday.

Angel Cruz, 30, a transit officer who suffered a pierced skull and a slashed face while serving a summons on a man on a Brooklyn subway platform, was in critical but stable condition after surgery.

Officer Robert Tejada, 35, was shot in the abdomen and ankle during a gunfight in a Harlem restaurant in which a 25-year-old man was killed.

Both officers were expected to make full recoveries.

The mayor saw a common link in the officers' shootings.

"While the specifics of the cases differ ... the culprit, ultimately, is the same: a man with an illegal handgun," the mayor said Wednesday night at a news conference in Greenwich Village, where he was joined by City Council Speaker Christine Quinn, a neighborhood resident.

Bloomberg has been a vocal advocate for wider tracking of illegal guns, and he has joined with mayors of dozens of U.S. cities to lobby Washington legislators on the issue. His administration has sued more than a dozen out-of-state gun dealers, arguing that they are responsible for many of the illegal weapons that end up in the city.