KHAN YOUNIS REFUGEE CAMP, Gaza Strip -- An explosion killed five Palestinian boys from the same clan as they walked to school Thursday, and Palestinian police said they believed the boys inadvertently set off an unexploded Israeli shell.
The children, ages 7 to 14, were hurled into the air and torn apart by the blast. Bloodied schoolbooks and scorched satchels were scattered across the sandy lot.
Israeli officials said the blast could also have been triggered by Palestinian-made explosives, but Palestinian officials blamed Israel.
The Palestinian information minister, Yasser Abed Rabbo, demanded that the United States and Europe exert greater pressure on Israeli Prime Minister Ariel Sharon to pull back troops from friction points. "We can't witness real security as long as Sharon and his government are seeking a military solution," he said.
Arieh Mekel, an Israeli Foreign Ministry official, said Israel shared the grief of the boys' families, but suggested that the Palestinians might want to use the deaths "for purposes of propaganda" as the region gears up for a fresh American diplomatic initiative.
Two U.S. mediators -- Assistant Secretary of State William Burns and retired Marine Corps Gen. Anthony Zinni -- are expected to fly in next week to push for a cease-fire.
Legislator Ran Cohen of the opposition Meretz party called for a joint investigation and demanded that Israeli troops stop firing tank shells toward civilian areas. Cohen, a colonel in the army reserves, said unexploded shells are "death traps" that can be set off by the slightest touch.
The Khan Younis refugee camp is a scene of frequent fighting between Palestinian gunmen and Israeli troops guarding the nearby Jewish settlement of Ganei Tal. An Israeli army post is about 800 yards from the site of Thursday's explosion.
Israel says it fires tank shells to silence Palestinian sniper fire from inside the camp toward army posts and Jewish settlements.
The blast happened at about 7:30 a.m. as a group of children walked toward a U.N. elementary school in the camp.
A Palestinian security official, Col. Khaled Abu Ola, said one of the children apparently kicked an unexploded Israeli shell lying on the ground. Abu Ola said his account was based on witness accounts and reports by police investigators.
The dead children were from the Al-Astal clan, one of the largest in the Khan Younis camp. Among the victims were two pairs of brothers, doctors said. The bodies were badly charred. "I saw parts of a leg flying in the air," said witness Sufian Abu Jamea, 15.
Also Thursday, three armed Palestinians in a jeep crashed through the gates of an Israeli factory in the West Bank near the town of Tulkarem, opened fire and slightly injured two workers, said the owner, David Yagouri.
Yagouri said he tried to return fire, but his pistol jammed. "They reversed out of the factory and escaped through the same gate which they had burst through," Yagouri told Israel Radio. Hospital officials said one of the injured workers was a Palestinian from Tulkarem, the other an Israeli Jew.
Earlier Thursday, Israeli forces raided Azzarieh, a Palestinian suburb of Jerusalem, and shut down three offices of Yasser Arafat's Palestinian Authority, the military said. The offices belonged to three different Palestinian security services.
The military said it acted to "prevent terrorist activity," but did not elaborate. Israel said the presence of Palestinian security forces in Azzarieh violated interim peace accords. The suburb is under joint Israeli-Palestinian control, with Israel remaining in charge of security.
Mekel, the Foreign Ministry official, said the raid was part of a government campaign to challenge the Palestinian Authority presence in east Jerusalem and nearby West Bank areas. The Palestinians claim the eastern part of the city, captured by Israel from Jordan in the 1967 Mideast war, as a future capital.