RAMALLAH, West Bank ? Breaking Yasser Arafat’s isolation, a U.S. envoy met with the Palestinian leader at his tank-encircled headquarters Friday on the bloodiest day of fighting since the beginning of the week-old Israeli military offensive.

At least 35 Palestinians including the suspected mastermind of a Passover attack that triggered the offensive died as gunmen and Israeli forces fought in Nablus, Tubas and Jenin in the West Bank. At least one Israeli soldier also died.

In advance of a planned visit to the region next week by U.S. Secretary of State Colin Powell, U.S. envoy Anthony Zinni traveled to the West Bank town of Ramallah for a 90-minute meeting with Arafat at his battered, encircled compound.

Arafat has been confined to a few rooms in his headquarters by Israeli troops since last Friday. Zinni was the first senior American official to meet with him during his confinement.

Arafat told Zinni that the Palestinians support a cease-fire deal negotiated last year by CIA chief George Tenet, according to his deputy Mahmoud Abbas. Israel and the Palestinians have been at odds over the timetable for implementing the agreement.

Ramallah has been declared a closed military zone by Israel, and Israeli troops fired stun grenades from close range at about two dozen journalists who were outside Arafat’s compound trying to cover the meeting.

Jerome Marcantetti, a cameraman with the LCI news channel of French broadcaster TF1, was slightly injured when he said an Israeli soldier fired at him after ordering him to leave an area 200 yards from the Church of the Nativity where he was filming Israeli armored personnel carriers. Marcantetti said X-rays showed a bullet fragment in his right thigh.

Meanwhile, Israeli troops and tanks pushed into another town in the northern West Bank on Friday despite a strongly worded appeal by President Bush on Thursday to stop the offensive. Defense Minister Binyamin Ben-Eliezer vowed, “We are finishing the operation we started.”

New violence on the northern border with Lebanon raised concerns that Israel could find itself bogged down on two fronts. The Lebanese government, trying to stem intensifying clashes along the frontier, said it seized a ready-to-fire Katyusha rocket and arrested nine Palestinian militants.

The day’s heaviest fighting came in the northern West Bank town of Nablus, where smoke from burning vehicles and buildings filled the air as Israeli tanks and helicopter gunships fought pitched battles with hundreds of Palestinian gunmen. Houses in the Balata refugee camp and the winding alleyways of the casbah, or old city, were peppered with heavy machine gun fire.

Israeli rockets rained on the city’s eastern market district, destroying hundreds of shops and stalls, witnesses said. Gunmen at one point holed up in a small shampoo factory, which was demolished by rockets while civilians living nearby cowered in their homes.

Palestinian sources and Israeli TV reports said among the dead in Nablus was Nasser Awais, a regional leader of the Al Aqsa Martyrs’ Brigade, a Palestinian militia that has claimed responsibility for scores of shooting and bombing attacks against Israelis over the past 18 months of conflict.

A 22-year-old man, Jamil Arboudi, blew himself up in a suicide attack that injured or killed four Israeli troops in Nablus, the Al Aqsa Martyrs’ Brigade said.

In the town of Tubas, the scene of the latest Israeli incursion, Israeli troops trapped six Palestinian gunmen in a house and then riddled their hide-out with tank shells and missiles fired from helicopters, killing them all, witnesses said.

Later, Palestinian sources confirmed reports identifying the six as members of the militant group Hamas. One of them was Qeis Odwan, who Israel TV called the mastermind of a March 27 attack at a Seder, or ritual meal, at the start of the Passover holiday.

Israelis bulldozed the building afterward and made people living nearby leave, witnesses said. Troops left the town soon afterward, they said.

Among at least 35 Palestinians killed in fighting Friday was a 14-year-old girl who had gone out onto her balcony in Tubas to look around. After the Israelis left, Palestinian security officials said three suspected collaborators with Israel, who had been held in the local jail for the past several months, were shot dead by Palestinian police.

The Israeli military also retrieved the bodies of five men in Bethlehem, apparently killed by fellow Palestinians as suspected informers for Israel.

In the northern West Bank town of Jenin and the adjoining refugee camp where three Israeli soldiers had died a day earlier shell fire and rockets trapped hundreds of families in their homes and prevented the evacuation of dozens of wounded, witnesses said. At least four Palestinians were killed, the Palestinians said.

“We can’t even look out the window,” said Jenin resident Noor Mansour. “My family and I hid in a room in our house. We couldn’t move.”

In addition to the two top militants killed Friday, Israel made an apparent attempt on the life of a leader of the Islamic Jihad militant group. Witnesses said an Israeli helicopter fired missiles on a car in the town of Hebron driven by Ziyad Shuweiki, but he escaped.

Five bystanders, including an 8-year-old boy, were injured, the witnesses said. The Israeli army had no immediate comment.

At the Church of the Nativity in Bethlehem, one of Christianity’s holiest sites, a standoff between Israeli troops and Palestinian gunmen inside continued into a fourth day. Four of about 60 priests trapped in the church came out Friday and left Bethlehem under Israeli escort, the military said.

In the Gaza Strip, some 10,000 supporters of the Islamic militant Hamas group rallied in the Jebaliya refugee camp. Sheik Ahmed Yassin, the Hamas founder, said the group would not stop attacks on Israelis.

International pressure was building on the Israelis to end their offensive. The U.N. Security Council passed a resolution early Friday calling on Israel to withdraw from Palestinian cities and towns “without delay.”

However, Israeli officials and newspaper editorials noted that Bush did not demand an immediate withdrawal from the West Bank and did not provide a timeline.

“From the outset it was said that we will be in the territories only for a few weeks,” Foreign Minister Shimon Peres told Israel’s Channel Two. “I think that the difference between what Bush demanded and the government decided is not great.”