Four adult Scout leaders from Alaska were killed Monday afternoon at the Boy Scout Jamboree in an electrical accident that apparently occurred when a pole from a tent they were setting up struck an overhead power line, officials said.

Three others, a Scout leader and two contract workers, were injured in the accident, which happened a few hours after the official noontime opening of the jamboree. The gathering draws thousands of Scouts every four years from across the United States and many foreign countries.

No Boy Scouts were injured.

The leaders were from the Anchorage area and represented the Scouts' Western Alaska Council, an official of that council said. Bill Haines said two of those killed and the injured leader had children with them at the jamboree, about 75 miles south of the District.

"It's a very tragic loss for all of us," Haines said.

The children, he said, were coping. "They are all being taken care of," he said.

Sheriff A.A. "Tony" Lippa Jr. of Caroline County said a preliminary investigation indicated that the pole had struck the power line but that authorities had not determined how it happened. "We're not sure if the poles shifted," he said.

Scout officials gave no details of how the accident occurred, other than to say that it was between 4:30 and 5 p.m. while the camp for the Alaskans was being set up. One person with knowledge of jamboree operations, who spoke on condition of anonymity because an investigation is underway, confirmed that a tent-support pole touched an electric line.

After the accident, witnesses saw a slender pole that protruded through the apex of a pyramid-shaped tent and appeared to be touching one or more overhead lines. The tent was one of two at the Alaskans' site that appeared to be intended for use as a group gathering place rather than for sleeping.

One of the two light-colored tents apparently had been fully erected. The other tent, where the accident apparently occurred, was cordoned off with yellow tape. The Scouts who might have stayed in that area had been moved.

Haines, in a telephone interview from Alaska, said the four men who died "were leaders in the Scouting community, longtime Alaskans. They were very instrumental in the council." It was the first jamboree for one of the men.

Lippa said the ages of three of the four were 42, 47 and 58.

All those injured were in stable condition at hospitals, the sheriff said. None of the men's names was released last night.

Officials said late last night that they expected the jamboree to continue but were not certain whether any adjustments to the schedule or participation might be made. Bob Dries, volunteer chairman of the event's national news and media operation, said: "I would expect the jamboree is going to carry on. Certainly, our sympathy is with the families. It's a sad day. The jamboree is about kids and having fun."

Renee Fairrer, director of national news and media for the jamboree also said the event would go on. She said the Alaska contingent had been separated from the others.

Gregg Shields, a spokesman for the Boy Scouts, said chaplains and grief counselors were meeting with the Scouts from the Western Alaska council. Those Scouts are "our primary concern right now," he said.

Haines said he did not know whether they would stay for the duration of the jamboree, which runs through Aug. 3. "We're going to do what the troop wants," Fairrer said.

Other Scouts from the general area in which the accident occurred appeared to be taking part late yesterday in planned activities. Some were seen setting up cots or reading. A Scout-run camp radio station interrupted its normal broadcast to report the accident.

Fairrer said the accident was being investigated by the Boy Scouts and the U.S. Army, which operates the base in Caroline County, about 10 miles east of Interstate 95 on Route 301, just south of the Rappahannock River.

She said late Monday that 32,000 Scouts and an additional 3,500 leaders had assembled to live for 10 days in what is essentially a huge tent city on the grounds of the base. President Bush is scheduled to address the gathering Wednesday night.

The accident, Fairrer said, occurred at the eastern edge of the campsite, which she estimated at seven to 10 miles from the fort's main gate. The base is about 76,000 acres; the Scouts are using about 5,000. Jamboree representatives said as many as 17,000 two-man tents might be pitched.

The site is supplied with electricity by the Rappahannock Electric Cooperative, Fairrer said. The utility last night said it was assisting in the investigation.

Over the past weekend, some of the Scouts have been in Washington, swarming over the Mall and through the monuments, a blur of khaki and neckerchiefs and patch-covered shoulders.

Hundreds of buses pulled into the military base yesterday to disgorge Scouts by the thousands. Officials said they came from 50 states and 20 foreign countries. At least 400 Scouts from the Washington region were scheduled to be on hand.

The jamboree has been held at the military base since the 1980s.

Staff writers Allan Lengel and Stephanie McCrummen contributed to this report. Weil reported from Washington.

Emergency workers examine the scene of the fatal accident at Fort A.P. Hill, the site of the National Scout Jamboree.