At least 4 people were killed when a tunnel filled with explosives detonated under the Israeli checkpoint on the Gaza-Egypt border near the town of Rafah this afternoon.
At least 10 people were wounded.
Witnesses said Israeli helicopters flew to the border crossing terminal and ambulances rushed in. The military said the explosion went off next to the terminal, and exchanges of fire were hampering efforts to evacuate the wounded.
A Palestinian militant giving his name only as Abu Majad said gunmen attacked the Israeli position after the blast. He claimed responsibility in the name of the Fatah Hawks, an offshoot of the mainstream Fatah Party, and the violent Islamic Hamas.
A Hamas official said 1.5 tons of explosives were set off in the blast. Israel Army Radio said the force of the blast collapsed some structures and damaged others.
Abu Majad said the attack was retaliation for what he called "the assassination" of Yasser Arafat, who died on November 11 in a French hospital. Some Palestinians claim he was poisoned by Israel .
Palestinians in the area said they heard a loud explosion followed by machine gun fire. Unconfirmed reports said two Palestinian suicide bombers were involved.
The attack followed several barrages of Palestinian mortar fire at Jewish settlements in southern Gaza.
Palestinians have dug many tunnels in the Rafah area, most of them under the border to be used for smuggling weapons and contraband in from Egypt.
Several times during four years of conflict, Palestinian militants have dug tunnels under Israeli bases in Gaza and detonated explosives. One of the attacks, in September 2001, collapsed the main Israeli fortress on the border.
AP