PITTSBURGH - In a scene that neighbors described as a war zone, a gunman fatally shot three police officers on Saturday morning as they responded to a domestic dispute between a mother and her son.

Chief Nathan Harper of the Pittsburgh police said the gunman, Richard Poplawski, 22, surrendered after a nearly four-hour standoff with SWAT team officers.

"We have never had to lose three officers in the line of duty in one call," Chief Harper said at a news conference in the lobby of police headquarters on the North Side of the city.

Police officers left the scene of a shooting Saturday in Pittsburgh. Three officers were killed and two wounded in the Stanton Heights neighborhood. (Ross Mantle/Getty Images)

The American flag and the Pittsburgh flag flew at half-staff just outside the building to honor the slain officers. They were Eric Kelly, a 14-year veteran of the force and married father of three daughters, and a pair of two-year department veterans, partners Stephen Mayhle, a married father of two daughters, and Paul Sciullo III, who was engaged to be married.

"No matter how many years they had on," Chief Harper said, "they paid the ultimate sacrifice."

The episode began around 7 a.m. in the Stanton Heights neighborhood of Pittsburgh, a blue-collar and middle class area made up mostly of two-story single-family brick houses but also of ranch houses like the one where Mr. Poplawski lived with his mother, Margaret Poplawski, 41.

The neighborhood is home to many of the city's firefighters and police officers, including Officer Kelly, who lived just four blocks away from the Poplawski home.

Officer Kelly had just ended his shift at 7:05 a.m. and was almost home when he heard that Officers Mayhle and Sciullo were responding to a domestic dispute nearby, said Deputy Chief Paul Donaldson, who wore a black band of mourning over his badge.

Chief Harper said the police had been called to the home at least twice before for domestic problems; neighbors said the visits were much more frequent - at least a half dozen calls in recent years when Mr. Poplawski and his mother got into fights.

Typically, the police "would come and be the peacemaker, and it would be over," said Geraldine Lejpras, who lives across the street from the Poplawskis. "But not this time."

Unknowingly, the officers walked into a deadly trap. Mr. Poplawski, wearing a bullet-proof vest, was armed with an AK-47 rifle, a .22 long rifle and a pistol.

Officer Sciullo was the first to the door, with his partner, Officer Mayhle, standing behind him and Officer Kelly just coming onto the scene.

When the door opened, Officer Sciullo was "immediately met with gunfire" and fatally shot in the head, Chief Harper said. Another shot struck Officer Mayhle in the head, also killing him.

A neighbor, Michele Ostrowski, said she saw the scene unfold when Officer Kelly arrived. "He got out of the car and I saw him get shot and he landed on the sidewalk," Ms. Ostrowski said in a telephone interview, her voice shaking.

Officer Kelly, who was critically wounded, managed to call for assistance. The next officer to arrive, Timothy McManaway, was shot in the hand as he rushed to help Officer Kelly, though he managed to fire at Mr. Poplawski, possibly wounding him in the leg.

For the next four hours, neighbors reported intermittent gunfire that could often last for a minute as both sides exchanged hundreds of shots, with Mr. Poplawski shooting from the bedroom window as his mother, who made the 911 call, took refuge in the basement of the home.

"It sounded like an actual war zone," said Georgia Marciniak, who lives just behind the Poplawskis' home. "It was absolutely scary."

A fifth officer, Brian Jones, was trying to slip behind the house when he broke his leg climbing a fence, Chief Harper said.

A neighbor directly across the street, Johann Devinney, said she saw the first two officers lying on the ground the moment she opened her front door just after 7 a.m. She quickly shut the door and hid with her husband in the back of the house.

Officers set up in the Devinneys' yard as well as at the house of Ms. Ostrowski, who lives cater-corner to the Poplawskis. The police used the Ostrowskis' Toyota Camry, which was parked in the driveway, as a shield. She said it was riddled with bullet holes.

At some point during the standoff, Mr. Poplawski's mother left the house, Ms. Devinney said, adding that she heard her shouting, "What are you doing with my son?"

The Pittsburgh Post-Gazette reported on its Web site that Mr. Poplawski had called a friend and former high school classmate, Edward Perkovic, from the scene around 8:30 a.m. The newspaper reported Mr. Perkovic recounting what Mr. Poplawski had told him: "Eddie, I'm going to die today. Tell your family and friends I love them. This is probably the end."

About 11 a.m., the police led Mr. Poplawski from the house in handcuffs. Ms. Ostrowski said his thigh and right shoulder were bloodied.

Neighbors said Mr. Poplawski had been kicked out of North Catholic High School and then was dishonorably discharged from the Marines three years ago, and had worked a series of short-term jobs in recent years.

But no one could explain why he did what he did on Saturday.

"I'd like to understand why," Deputy Chief Donaldson said. "It's senseless."

The killing spree here came less than a day after a gunman murdered 13 people at an immigrant services center in Binghamton, N.Y., before killing himself, and two weeks after a parolee shot and killed four police officers in Oakland, Calif.

Chief Harper said Pittsburgh was generally unaccustomed to this type of violence but had recently endured a spate of gang-related activities.

Councilman Doug Shields said he had been attending a rally at Heinz Field calling for peace in some of the city's more violent neighborhoods when he learned of the killings.

"This event certainly puts a whole different light on that rally," Mr. Shields said. "What can we do other than pray for the dead and those were hurt?

"Someone with an AK-47 today was angry enough to use it. It makes me want to be sure we're reaching out to the community."

Liz Robbins reported from New York, and Sean D. Hamill from Pittsburgh. Jack Styczynski contributed research from New York.