RAMALLAH, West Bank ? Israeli troops backed by tanks swarmed into Yasser Arafat’s headquarters Friday, punching holes in walls and fighting room to room as the Palestinian leader huddled in a windowless office and made frantic appeals to world leaders by cellphone.

Five Palestinians and an Israeli soldier were killed as Israeli forces took over the West Bank city of Ramallah and Arafat’s sprawling compound, where 25 Palestinians were wounded and 60 detained.

In the latest Palestinian attack, an 18-year-old woman blew herself up at the entrance of a Jerusalem supermarket, killing herself and two Israelis. The Al-Aqsa Brigades, a militia close to Arafat’s Fatah movement, said it sent the bomber.

The Ramallah operation was described by Israeli officials as the first stage of a much larger assault aimed at destroying the “terrorist infrastructure” that Israelis blame for the hundreds of deaths they have suffered in 18 months of relentless violence. More than a thousand Palestinians also have died.

Israel said it had no plans to kill Arafat but wanted to isolate him.

Throughout the day, Israeli tanks shelled buildings in the compound and soldiers entered buildings and traded fire with Palestinians. By nightfall, Arafat was trapped in his three-story office building, which was plunged into darkness when soldiers cut off electricity and destroyed a generator. Phone links were blocked, leaving Arafat with only a cell phone to connect him with the outside world.

Arafat was in a windowless room, following events on television, giving phone interviews to Arab satellite TV channels and speaking by phone to more than a dozen world leaders. Arafat pleaded for immediate international intervention, but was not given real promises, one of his aides said.

Among those the Palestinian leader spoke with were Lebanese Prime Minister Rafik Hariri and Arab League leader Amr Moussa.

A submachine gun placed on the table in front of him, Arafat was defiant. “They want me under arrest or in exile or dead, but I am telling them, I prefer to be martyred,” he said in a telephone interview with Al-Jazeera, the Arab satellite television channel. “May God make us martyrs.”

In an interview with CNN, Arafat assailed Israel, saying the Palestinian people were “fighting this tyranny.” He said Palestinians will continue “in the face of … this terrorist occupation.”

In yet another interview with Jordanian state-run television, Arafat described Israeli Prime Minister Ariel Sharon as “bloodthirsty” and bent on “blowing up” a collective Arab peace initiative endorsed Thursday.

“Is this the right answer to the Arab summit and the proposal of Saudi Crown Prince Abdullah?”

Arafat added that the United States “could have ordered him (Sharon) to end the attacks. Why are they quiet despite all that is taking place?”

In Washington, Secretary of State Colin Powell said Israeli Prime Minister Ariel Sharon had told the United States that Arafat would not be harmed. Powell urged the Israeli prime minister to use restraint and consider the consequences of escalation. But he added: “Let’s be clear about what brought it all to a halt terrorism,” and called on Arafat to put a stop to violence.

Despite the violence, U.S. truce envoy Anthony Zinni continued his mission, meeting with Palestinian negotiator Saeb Erekat on Friday and speaking to Arafat by phone.

Erekat said Israel’s “endgame is to kill Arafat,” an accusation that Sharon spokesman Ranaan Gissin dismissed as “nonsense.”

The latest escalation began with a suicide bombing Wednesday in an Israeli hotel banquet hall that killed 22 diners during a Passover Seder, the ritual meal at the start of the weeklong Jewish holiday. It was followed by attacks on two Jewish settlements Thursday and Friday that killed six Israelis.

On Friday morning, after an all-night session, his Cabinet declared Arafat an “enemy” and said the Palestinian leader would be completely isolated. Israel began calling up thousands of reserve soldiers, and the mobilization was expected to reach 20,000 troops, the largest in a decade.

Hours later, Israeli troops and two dozen tanks swarmed into Arafat’s walled compound an area the size of a city block with a jumble of several interconnected buildings, surrounded by a high wall with three gates.

Israeli troops know every inch of Arafat’s three story-office building it was the Israeli military headquarters in Ramallah until Israel withdrew from the city in 1995. The bottom floor has guard rooms, the middle floor houses Arafat’s office, dining room and sleeping quarters, and the top has more offices.

In Friday’s assault, heavy tank and gunfire hit the building’s first and third floors, Information Minister Yasser Abed Rabbo said the first time Israel directly targeted the building. Israeli snipers took positions on rooftops, and tanks shelled the intelligence headquarters in the complex.

Israeli troops broke into structures adjacent to Arafat’s offices and punched holes in walls, moving room to room toward his building. At one point, they broke through a wall into the office building itself and traded fire with Palestinians through the hole, the Palestinians said.

But the military said its soldiers did not enter the building. Maj. Gen. Yitzhak Eitan, commander of Israeli troops in the West Bank, said troops were in control of the whole compound except Arafat’s offices. He said large amounts of weapons were found and about 60 people were detained. Abed Rabbo told CNN those detained were unarmed, mostly secretaries and drivers.

Earlier this month, the Israeli military carried out an extensive operation in the West Bank and Gaza Strip, sending 20,000 soldiers into towns, villages and refugee camps in a hunt for Palestinian militants. That operation was the biggest since Israel’s 1982 invasion of Lebanon.

Zinni, the U.S. envoy, had reported some progress toward a cease-fire this week. Israel had accepted Zinni’s timetable for implementing a truce with some reservations, while the Palestinians sought more clarifications.

Thursday evening, with Israeli retaliation for the Passover bombing already imminent, Arafat said he was ready to immediately implement the U.S. truce plan without conditions. But he stopped short of formally declaring a cease-fire.

Sharon later said Israel had sought a cease-fire but only received “terrorism, terrorism and more terrorism.”

The Israeli assault sparked protests by Palestinian refugees in camps in Syria, Jordan and Lebanon. Arab leaders said the assault was aimed at wrecking an unprecedented peace initiative approved at an Arab summit on Thursday, offering Israel normal relations in exchange for its withdrawal from territory captured in the 1967 Mideast war.