After a rash of shootings over the last week that killed three people, including a 15-year-old girl, and wounded six, Pittsburgh Police Chief Nate Harper said he plans to increase police patrols in Oakland and the hilltop communities of Beltzhoover, Allentown, Mount Washington and St. Clair Village.

"The O.K. Corral is not in the city of Pittsburgh," Chief Harper said at a news conference yesterday. "This is unacceptable behavior."

There will be at least 18 additional officers on the streets in those neighborhoods on Thursday, Friday and Saturday nights.

In Oakland, where a 21-year-old male and a 22-year-old male were wounded yesterday in an early-morning shooting near the McDonald's on Forbes Avenue, city police will team with University of Pittsburgh police patrols.

Chief Harper expressed disappointment that there wasn't more community outrage after the death of 15-year-old Raymond Reese, who was killed Sunday in a drive-by shooting on Pasadena Street on Mount Washington.

He called on groups like the NAACP, the Urban League and the Black Political Empowerment Project to use their influence to try to stem the violence.

"I hope city of Pittsburgh residents have not become desensitized," he said. "We need as much help as we can to get these communities back to being safe."

Tim Stevens, chairman of B-PEP, said Chief Harper's decision to single out his group was surprising. They had spoken on the phone this week to organize the chief's appearance at Duquesne University on July 8, when the Coalition Against Violence -- which was formed last year -- will present a detailed report on long-term strategies for combating crime and gun violence in the region.

"It will not sit on a table. It will be used," Mr. Stevens said of the report.

He said Chief Harper had participated in several meetings with members of the coalition.

"Nate knows me personally. He has my number. If he thought we should collectively come out, none of us would have said no," Mr. Stevens said. "Obviously it hurts all of us when we hear that another young person was killed by senseless violence."

Ms. Reese, who had just finished the ninth grade at Pittsburgh Public Schools' Student Achievement Center in Homewood, was the first homicide victim of a bloody week. The Mount Oliver girl was killed in an early-morning shooting at 78 Pasadena St., where a group of teenagers was gathered on the house's porch.

Police said she was an innocent bystander.

Two other teenagers were wounded, including 16-year-old Jesse Robinson III, who was partially paralyzed. An unidentified 15-year-old girl from Knoxville was shot in the arm.

Chief Harper said police are in discussions with the city's Bureau of Building Inspection about condemning the property, which has been a trouble spot. They haven't determined a motive for the shooting.

Early Thursday, a second Mount Washington shooting took place at Sonny's Place, a Shiloh street bar, killing Brandon Alton, 23, who was with several friends when a fight broke out with another group of men.

Police suspect that the fight was connected to a feud between rival groups from Beltzhoover and St. Clair Village. They were trying to determine if there was a connection with the Pasadena Street shooting.

The third homicide occurred on Monday afternoon, when Kenneth Woods, 30, was shot at Bentley Drive and Nigh Way in the Hill District. Police were still investigating yesterday.

Around 4 a.m. yesterday, a 23-year-old female and a 24-year-old male were shot in the 400 block of Beltzhoover Avenue. They were both in stable condition at Mercy Hospital.

Police have not identified the victims, nor have they identified the victims in the Oakland shooting, which occurred a little before 3 a.m. yesterday.

Both men were taken to UPMC Presbyterian; the 21-year-old, from the North Side, was listed in critical condition and the 22-year-old, of Oakland, was in serious condition. One of the men had been involved in a fight earlier that night at the Sphinx Cafe, at Atwood and Bates streets, where police broke up a crowd of about 100 people outside.

During the new patrols, police will be stopping young people under 17 who are out past the city's curfew, Chief Harper said. In July and August, the city's curfew requires that youths younger than 17 be off public streets by 11 p.m. Sunday through Thursday and by midnight on weekends (the curfew starts an hour earlier in other months).

The number of homicides in the city so far this year is 34, up from 30 or 31 at this time last year, police said.