Prince George's County police commanders pledged yesterday to station more uniformed officers for longer hours along the county's most dangerous streets after a spate of violence that has left seven people dead in five days.

The 1,200-member department -- which has seen its staffing levels gradually fall over the past two years -- will be bolstered with overtime assignments and the reallocation of resources, including the positioning of undercover detectives and narcotics officers in the areas where "crime seems to be the greatest," said Deputy Chief Jeffrey Cox.

"We're going to try to increase our proactive policing during the late-night hours," said Cox, who oversees the department's patrol division. "We will increase the numbers on the streets to answer routine calls for service and conduct traffic enforcement and criminal enforcement. Those officers will be able to respond right away and can track down witnesses and possible suspects."

Cox also vowed to post officers in specific neighborhoods and outside nightclubs where violence has repeatedly flared, including areas where drug dealing has been a persistent problem. Some of the recent homicides, Cox said, "seem to be fueled by the drug trade," a matter that concerns the department's leaders.

Since Thursday, homicide investigators have responded to seven slayings across the county, from College Park to Glenarden. The most recent occurred late Monday in the 6500 block of Insey Street in Forestville, when Jeffrey T. Jones Jr., 21, was fatally shot about 11:15 p.m.

In that killing, police said, Jones was standing with three friends when a group of men announced a robbery. During the robbery, Jones was shot in the upper body, police said. He was later pronounced dead at the scene. His friends were grazed by bullets.

No arrests have been made in any of the seven slayings, police said, and few tips or leads have turned up.

Percy Alston, president of the police union, applauded the promise of overtime assignments but said the changes will do little to address rank-and-file officers' increasing concern over staffing shortages. By the union's count, about 450 officers are assigned to patrol the county, or about 39 percent of the force. Those officers respond to 2,000 calls for service on the average day.

"When you're only responding to calls for service and only doing reactive law enforcement, then your ability to prevent crimes is severely hampered," Alston said, adding that in recent weeks, entire police districts have been patrolled by two or three officers. On Monday night, for example, just four officers were on duty in the Clinton district, an area that encompasses more than 100 square miles, he said.

"Not only are those types of situations unsafe for our officers, but they are unsafe for our citizens," said Alston, president of Fraternal Order of Police Lodge 89. "If there's no visibility, then there's no deterrent to crime."

Although homicides are nearly impossible to predict or avert, Alston said, there is "some relationship" between the department's staffing shortages and the recent wave of violence.

"When you're able to do proactive law enforcement, you can check suspicious vehicles or suspicious people who seem out of place," he said. "In doing so, you can possibly remove someone from the street who has the propensity to commit a homicide or someone who has an open warrant and is dangerous."

Still, Cox said he remains optimistic that over the next several months, the cases will be closed and the homicide rate will fall. He said overall crime in the county has declined almost 2 percent this year, despite the recent surge in killings. Police have responded to 94 killings this year, compared with 86 for the same period in 2003, an increase of 9 percent.

"We don't want to give the impression that crime is out of control in Prince George's and the police aren't making headway," Cox said. "The investigators are working very hard to close the cases, and the officers on the streets are working hard to prevent the crimes from occurring."