BOWIE, Md. (REUTERS) — A teen-ager was shot and critically wounded Monday at a suburban Washington school, the latest victim of an elusive sniper accused of killing six people at random around the U.S. capital, police said.

The 13-year-old was shot once in his upper body at 8 a.m. as he entered his school in Bowie, Maryland, after he was dropped off by an aunt. Hospital officials said the boy was in surgery and remained in critical condition.

“The projectile that was recovered from our victim this morning has been linked to our sniper. We are continuing to follow up on leads,” Prince George’s County Police Chief Gerald Wilson told a news conference.

Monday’s incident followed a spate of shootings around the Washington, D.C., area that began Wednesday, with at least one gunman firing a high-velocity rifle at apparently unrelated victims in crowded public places.

Dr. Martin Eichelberger, the boy’s surgeon, said a single bullet pierced the teen-ager’s spleen, stomach, pancreas, lung and diaphragm. There was no exit wound.

“He has weathered a significant injury, and at this point we are satisfied how he has got through surgery,” the surgeon told reporters outside Washington’s pediatric hospital.

Eichelberger removed one shard of the bullet, which shattered inside the boy’s body, and gave it to ballistics experts.

Six people were killed and one seriously wounded in last week’s shooting spree, which had ceased by Friday afternoon. Police ballistics experts say that the same gun was used in at least four of the attacks.

President Bush called the shootings “cowardly and senseless acts of violence” and said he had committed federal resources to assist investigators and communities affected.

“I applaud the state and local law-enforcement officials who are working around the clock to help solve these heinous crimes and protect our citizens,” Bush said in a written statement. “Laura and I send our thoughts and prayers to the victims and their families.”

The spate of violence has rattled Montgomery County and Prince George’s County, both just north of Washington, D.C. Communities there, where many residents commute to jobs in the Capitol, are still unnerved by last year’s Sept. 11 strike on the Pentagon and the letters sent afterward containing anthrax spores.

“People really just can’t understand how someone can do this . . . the senseless killings, the random killings, and the feeling they are continuing,” Montgomery County executive Doug Duncan told reporters.

Another man was shot in Washington while sitting in his car Monday, but Washington police spokesman Joe Gentile said the man was apparently shot during an attempted robbery unrelated to the sniping attacks.

Students at the school said Monday they heard a loud noise and then saw the victim slump over, then return to his aunt’s car to be driven to the hospital.

Although other students on the school grounds witnessed the shooting, none reported seeing a gunman or car from which the killer might have fired.

The six people killed last week had no apparent connection to one another. They were shot while going about routine activities like mowing a lawn, buying gasoline, vacuuming a car and sitting on a park bench.

There were no known witnesses to the murders last week, but one person reported seeing a white delivery truck with two men inside speeding away from a shooting outside a post office.

The sniper has been described by police as a skilled marksman who needed only one shot to murder his victims.