Palestinian militants in the West Bank town of Jenin issued a belligerent challenge Tuesday to the new Palestinian leadership's efforts to rein in militant groups, shooting in the air and demanding that the visiting security chief, Interior Minister Nasser Yousef (search), leave the area immediately.

A furious Yousef immediately fired his local security chief, ordered hundreds of police reinforcements to the building and demanded the arrest of the militants.

However, the militants' leader, Zakariye Zubeydi (search), later met with Yousef and apparently resolved the issue without any arrests, underscoring the government's difficulty in dealing with security.

The issue is one of the thorniest facing new Palestinian leader Mahmoud Abbas (search), who is working to reform his security forces and end chaos in Palestinian areas without angering the militants, who are a powerful force in Palestinian life and are seen as heroes by many Palestinians.

Since taking office last month, Abbas has deployed forces throughout the Gaza Strip to prevent militants from firing rockets on Israeli targets and negotiated a temporary halt to all attacks on Israel. He has resisted Israel's demands for a crackdown on the militants, fearing it could set off a civil war.

Abbas told an international conference in London on Tuesday he was committed to bringing order to Palestinian areas.

"The most important message is our readiness, our full readiness to work for the internal security," he said.

But the limits to which Abbas — and even the leaders of the militant groups — can control the attackers was exposed Friday night when, despite the truce, a suicide bomber blew himself up outside a Tel Aviv nightclub, killing five Israelis.

On Tuesday, Israel also linked Islamic Jihad (search) to a failed attempt to blow up a car with half a ton of explosives, the largest bomb assembled by militants in more than four years of fighting.

Islamic Jihad leaders claimed responsibility for the Tel Aviv bombing, but blamed the attack on a local rogue cell working on orders from the Lebanese guerrilla group Hezbollah (search) and not from Islamic Jihad leaders in the Palestinian areas.

As part of Palestinian efforts to control the militant groups, Yousef, a tough ex-general, was meeting Tuesday with local officials in the government headquarters in Jenin when Zubeydi, local leader of the Al Aqsa Martyrs' Brigades (search) militant group, and six of his followers approached the building and began firing in the air and demanding Yousef leave.

Security officials prevented Zubeydi from entering the building and brief scuffles broke out before he and his followers left.

Zubeydi said he was upset Yousef had not coordinated his visit with him.

"Every city has its own gate, and Nasser Yousef did not come through the proper gate of Jenin," he said.

Yousef responded by instantly firing the local security chief, Fayez Arafat, bringing 600 police reinforcements to the headquarters, and demanding Zubeydi's arrest.

"We are not leaving Jenin before we have arrested this bunch of criminals," Yousef said.

He quickly backed down, however, holding a meeting with Zubeydi, who returned to the building armed with a rifle and wearing a bulletproof vest.

Zubeydi left without being arrested and Yousef left without commenting.

Meanwhile, Israeli linked Islamic Jihad to Monday's failed car bombing and three other plots.

The military discovered the car filled with explosives parked at a junction near Jenin when an officer noticed wires sticking out of it. A long cable snaking from the car was attached to a battery and video camera, which was to document the attack, military officials said.

The army detonated the 1,100-pound car bomb in a controlled explosion.

Military officials said the same group behind the Tel Aviv bombing might have been behind the car bomb.

Security officials also revealed Tuesday that a captured Islamic Jihad militant told his interrogators of another car bomb plot, plans to carry out a rocket attack on the Israeli town of Afula, and preparations for a double suicide bombing against a Jerusalem school.

The army said the suicide bombing had been foiled and the attempt to smuggle rockets into the West Bank failed for "technical reasons."

The militant, Jibril Zubeydi (search), Zakariye Zubeydi's brother, was arrested two months ago, the security officials said on condition of anonymity.

Israeli analysts said the new violence was the result of an apparent fracture within the Islamic Jihad leadership, with the Syria-based leaders determined to scuttle the fragile cease-fire.

Secretary of State Condoleezza Rice (search) said those behind the bombing would have to be dealt with.

"Obviously, when you have Palestinian Islamic Jihad taking responsibility, then something needs to be done about that because they are clearly challenging directly the Palestinian Authority," Rice said en route to the London conference.