Under the cover of fog, two heavily armed Palestinian militants on Saturday used a rope and ladder to scale a massive border wall and enter Israel from Gaza, attacking an army base with explosives and gunfire before they were tracked down and killed by Israeli troops.

The infiltration was the latest incident in a spike of violence that left eight Palestinians dead in less than 24 hours. Among those killed was an 11-year-old boy shot Friday 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.

In the most brazen attack, militants tunneled into Israel in June 2006, killing two soldiers and capturing a third. The captured soldier, Cpl. Gilad Shalit, remains in captivity. Tensions have risen further since the Islamic militant group Hamas seized control of Gaza in June.

In Saturday's early-morning raid, the militants took advantage of darkness and weather conditions to slip into Israel near the Erez border crossing, said Col. Moni Katz, an Israeli commander. "There was thick fog that enabled us to see only a few meters ahead," he said.

Katz said a total of four militants approached the wall, but only two climbed into Israel. Soldiers showed reporters the rope the attackers used to slide down.

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.

Lev-Ram said the militants attacked an army post at Erez — the main passageway for people going in and out of Gaza — 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. Authorities set up checkpoints and conducted searches along the border for several hours as precautionary measures. Two soldiers were lightly wounded in the fighting, the army said.

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.

An Al Aqsa official confirmed the fog had created a "golden opportunity," adding the border farming community of Netiv Haasara was the target. He was not authorized to talk to the media and spoke on condition of anonymity.

The groups also issued a farewell video made by the two dead attackers in which the men, wearing green and brown camouflage, read verses from the Koran and said the attack was for the sake of God and the Palestinian homeland. The men brandished automatic weapons, and flags of the three groups were in the background.

In other violence, militants detonated a bomb near the border fence in southern Gaza, lightly wounding four soldiers, the army said.

The volatile border with Gaza has grown increasingly tense since Hamas took control of Gaza in June after five days of fighting against the rival Fatah movement. Israel considers Hamas a terrorist group and has stepped up its activities in Gaza, launching incursions to halt rocket attacks and searching 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.

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 caught in the crossfire, Palestinian officials said. The boy, who lived in Israel, was visiting relatives, family members said.