Updated

A guard killed an attacker who planned to blow up the "Studio 49" club early Friday, where about 200 people were partying after midnight, Tel Aviv police commander Yossi Sedbon said.

Thursday morning, a bomb went off under a tanker truck entering Israel's main fuel depot next to Tel Aviv, but the blast did not ignite the huge fuel tanks, Sedbon said, calling it "a miracle."

The tanker attack was part of what experts said is a relentless new campaign by Palestinian militants to carry out a large-scale terror attack. Disasters were narrowly averted in both attacks.

"A big tragedy was averted here," said Sedbon, commenting on the attempted nightclub bombing, the second near-miss in his city in less than 24 hours.

The guard, Eli Federman, 36, told reporters that he saw the car turn sharply and race toward the club, and he opened fire, hitting the attacker.

Federman said the attacker started falling out of the car, setting off a blast. "Then I fired the rest of the bullets into his head," killing him, he said.

There was no claim of responsibility for either attack.

In Gaza City early Friday, witnesses said Israeli troops entered the Zeitoun neighborhood and blew up three small factories. No one was hurt, and one person was arrested, they said. The Israeli military had no immediate comment. The incursion followed several incidents of mortar and rocket fire at Jewish settlements in Gaza.

Israeli experts expressed concerned about a new type of Palestinian terrorism — attacks on strategic targets.

The blaze at the fuel depot underlined Israel's vulnerability to such attacks. Despite decades of warnings by security experts and environmentalists, the depot is still located in the middle of Israel's most densely populated area, near Tel Aviv.

Earlier this week, Israeli security officials released details of a thwarted attempt to set off a ton of explosives under Tel Aviv's tallest office building complex.

"The terror organizations [have] moved to a new phase of attacks," said Ehud Yatom, a former security official.

He told Israel Radio that the attempted attack at the fuel depot had similarities with the Sept. 11 attack on the World Trade Center, where airborne terrorists used thousands of pounds of jet fuel as a huge bomb.

The bomb that exploded at the fuel depot was planted under the truck as it was parked overnight in front of the driver's home south of Tel Aviv, Israel Radio reported, and security officers failed to spot it when the truck entered the depot.

The blast set fire to diesel fuel that leaked from the tanker and burned the cab to a crisp, but firefighters were able to put out the blaze before it spread to above-ground tanks that contain millions of gallons of fuel and gas.

"A huge disaster has been averted." said Sedbon. "It was a miracle."

Israel TV showed a map with concentric circles starting at the Pi Glilot depot, predicting widespread destruction throughout the Tel Aviv area if the depot exploded.

The two attacks followed a homicide bombing Wednesday in Rishon Letzion, nine miles south of the fuel depot. The bomber and two Israelis were killed. A militia affiliated with Palestinian leader Yasser Arafat's Fatah movement claimed responsibility, while the Palestinian Authority denounced the bombing, saying it would give Israel an excuse to retaliate.

Israeli Defense Minister Binyamin Ben-Eliezer acknowledged that Israel's recent military operation in the West Bank had heightened motivation among militants to carry out attacks. "We are faced with waves of suicide bombers," he said.

On March 29, the Israeli army launched an offensive into the West Bank in response to an earlier wave of Palestinian attacks, taking over main Palestinian cities and refugee camps, fighting gunmen, making arrests, blowing up bomb factors and confiscating weapons.

After another homicide bombing in Rishon Letzion on May 7, when a bomber killed 15 Israelis, Israel was poised to launch an attack on Gaza, but called it off at the last minute. There were no immediate signs that Israel planned to retaliate for the latest attacks, though Israeli officials blamed Palestinian leader Yasser Arafat.

In a leaflet sent to The Associated Press, the Al Aqsa Martyrs Brigades militia, linked to Fatah, claimed responsibility for the latest homicide bombing, saying it was retaliation for Israel's killing Wednesday of Mahmoud Titi, 30, the militia leader in the West Bank city of Nablus, and three other Palestinians

Thousands of Palestinians joined their funeral procession on Thursday, chanting "revenge, revenge."

In Nablus, Palestinian security officials said two Palestinians were killed when a bomb they were constructing in a house exploded prematurely.

Also Thursday, Israeli soldiers arrested 22 Palestinians in four separate raids in the West Bank, including the city of Hebron, the military said.

In a political development, five members of a Palestinians' Central Elections Committee submitted their resignations to Arafat after he failed to set a date for new elections, an official close to the panel said. There was no comment from Arafat's office.

Arafat has been under heavy pressure from Israel, the United States, Europe and his own people to reform his corruption-ridden regime, call elections and streamline his security forces.

The Associated Press contributed to this report.