Three sons of Boy Scout leaders killed in an electrical accident at the National Scout Jamboree in Virginia have returned home to Alaska, officials said Tuesday.

The accident happened on the opening day of the gathering at a U.S. Army base in Bowling Green, south of Washington.

The Scout leaders were erecting a tent Monday night when a pole apparently hit an electrical wire; four were killed, making it the worst such accident in jamboree history.

The victims were identified Tuesday as Michael J. Shibe, 49, Mike Lacroix, 42, and Ronald H. Bitzer, 58, of Anchorage, Alaska; and Scott Edward Powell, 57, of Perrysville, Ohio.

Alaska Gov. Frank Murkowski issued a statement offering his condolences to the victims' family members and troop members.

"These individuals were killed while serving Alaska's young people and I admire and thank them for that service," he said.

One other leader from Alaska and two contract workers were hospitalized in a stable condition. No Boy Scouts were seriously injured.

"Our hearts go out to the families of these devoted Scout leaders who gave so much to their sons, their troops, and their communities," the Boy Scouts of America said in a statement.

Flags flew at half-mast outside Scouts Canada headquarters. Four leaders and 16 scouts from Ontario are attending the jamboree.

"... Our members have all arrived safe and well, and everyone is doing as well as can be expected at this time," said Susie Mackie, a Scouts Canada spokesperson.

The organization said the accident was under investigation but did not elaborate on the incident, which occurred as the group was setting up camp. The tent appeared to be intended for large gatherings rather than for housing, the Washington Post reported.

National Jamboree organizers said increased safety procedures were being put in place in the wake of the accident.

Monday's deaths came a day after a Boy Scout volunteer from North Carolina was taken to a hospital where he died of an apparent heart attack.

The Scouts vowed to continue their Jamboree despite the accident. A memorial service was planned at Wednesday's opening ceremony and a chaplain and grief counsellors were available.

"We are family, and this is like something has happened to four members of our family," Scouts spokeswoman Renee Fairrer said. "We are all hurting."

More than 40,000 Boy Scouts, leaders and volunteers from around the world are attending.

It runs through Aug. 3 with U.S. President George Bush scheduled to speak Wednesday evening.

The Boy Scouts of America have held their national Jamboree every four years since 1937. The next gathering is set for 2010, the Scouts' 100th anniversary.

With a report from CTV's Jill Macyshon