The incident raised the death toll to eight Palestinians in less than 24 hours of Israeli-Palestinian violence. Among the dead was an 11-year-old boy who was killed while visiting relatives in a West Bank village.

Militants frequently attack the Israeli border, but Saturday's infiltration was one of the few times they have managed to slip through the heavily fortified fence enclosing Gaza. The army showed reporters how the militants scaled the 8-meter (25 foot) concrete fence with a ladder and climbed down the Israeli side with a rope.

Maj. Tal Lev-Ram, an Israeli army spokesman, said there was "an intention to carry out a large attack in Israeli territory." He said the militants were heavily armed "head to toe" with grenades and automatic weapons, and were headed toward communities in southern Israel when they were stopped. Two Israeli soldiers were lightly wounded in the clashes, the army said.

Lev-Ram said the militants entered Israel near the Erez border crossing, attacked an army post and continued into Israel. Ground forces were dispatched and killed the infiltrators after a brief chase. He said the militants were about 700 meters (yards) inside Israeli territory when they were shot.

After the clash, their bodies were dragged away by a small robotic crane — used in case the men were rigged with explosives.

In Gaza, three militant groups — the Popular Resistance Committees, the Democratic Front for the Liberation of Palestine and the Al Aqsa Martyrs' Brigades — claimed responsibility. In a joint statement, they said three gunmen participated in the attack. Two were killed after a "long battle," and the fate of the third was unknown, it said.

Lev-Ram said the claim of a third militant entering Israel was wrong, and if there were other attackers, they probably turned around and stayed in Gaza.

Still, the army and police set up checkpoints and conducted searches on both sides of the border while a helicopter flew overhead as precautionary measures. By early afternoon, the checkpoints had been removed and the situation was back to normal, the army said.

In other violence, militants detonated a bomb near the border fence in southern Gaza, lightly wounding four soldiers, the army said. Militants also fired several mortars into southern Israel, causing no injuries, it added.

The volatile border with Gaza has grown increasingly tense since the Hamas militant group seized control of the coastal strip in June. Israel considers Hamas a terrorist group and has stepped up its activities since the Gaza takeover, frequently launching incursions into Gaza to halt rocket attacks and to search for tunnels that can be used by militants.

The army also frequently thwarts attempted infiltrations, including one on Friday night in which two militants were killed after firing at Israeli soldiers on the Israeli side of the border. Troops entered Gaza late Friday and shot the gunmen after a brief chase, the army said.

There was no official word on the identities of the two militants, and Palestinian medical officials said they were still unable to retrieve the bodies early Saturday.

In the West Bank, meanwhile, Israeli forces opened fire at a car full of Palestinian gunmen in Jenin early Saturday, killing two Islamic Jihad militants inside and wounding two others, Palestinian security officials said.

The army said it fired at the vehicle after spotting armed men inside.

On Friday, an Israeli raid in search of militants in a West Bank village sparked a firefight that left two Palestinians dead, including an 11-year-old boy, Palestinian officials said.

Mahmoud Ibrahim Karnawi, 11, was shot after Israeli troops moved into Saida village in the northern West Bank, witnesses said. Relatives said the boy lived in Israel and was visiting relatives at the time.

They said the troops were trying to arrest his older half brother, a wanted Islamic Jihad militant.

Neighbors said the boy was inside the family and hit in the crossfire of a gunfight. Hospital officials said an Islamic Jihad militant not related to the boy also was killed.

A member of the Israeli paramilitary border police was lightly wounded, the army said.