Associated Press WriterRAMALLAH, West Bank (AP) -- Israeli tanks encircled Palestinian leader Yasser Arafat's badly damaged headquarters Monday, and Prime Minister Ariel Sharon told his party Israel was preparing a large operation in the Gaza Strip against the militant Hamas movement.
Sharon's spokesman, Raanan Gissin, said the prime minister spoke to members of his Likud Party hours after Israel delivered the first blow of the new offensive -- a helicopter missile strike on two cars carrying Hamas members, killing six Palestinians and injuring five in the southern Gaza Strip at Rafah.
Four of the dead belonged to Hamas, the movement said. Israel said it targeted and killed Yasser Rizik, a "senior Hamas activist" who was allegedly behind a January attack that killed four soldiers.
Also in Gaza, Palestinian police surrounded the Gaza City home of Hamas spiritual leader Sheik Ahmed Yassin, and Palestinian authorities said he was under house arrest. However, Yassin invited journalists inside and said he was unaware of any such order.
After brief scuffles between Hamas supporters and police, masked Hamas gunmen patrolled the sandy streets outside the house, while police pulled back several hundred yards.
The latest turbulence came as both Israelis and Palestinians awaited an address by President Bush on proposals for fresh peacemaking efforts and guidelines for a future Palestinian state.
Administration officials said Monday the address was tentatively planned for the afternoon, but Bush had not made a final decision.
The speech was put off last week because of escalating violence, which included three major Palestinian attacks that left more than 30 Israeli civilians dead, and prompted the Israeli invasion of the West Bank.
In Washington, there's been widespread speculation that Bush's plan will call for a provisional Palestinian state. The details are not known, though the idea has so far received a cool reception in the Mideast.
Sharon said last week that the time was not "ripe" for any sort of Palestinian state.
Palestinian Information Minister Yasser Abed Rabbo said that "any initiative or any idea is worthless today, because what's important is the Israeli invasion."
Rabbo said it was "the responsibility of the American administration to pressure the Israelis to pull back before talking about initiatives and peace talks."
In Ramallah, the Palestinian political headquarters in the West Bank, Israeli soldiers atop armored personnel carriers flashed V-for-victory signs as dozens of tanks and armored personnel carriers rolled into the city under the cover of two helicopters.
The troops took up positions around Arafat's offices, where bulldozer quickly built earthern barriers at the front gate and on nearby streets. More than 20 tanks were parked on the streets that surround Arafat's compound Monday afternoon.
Israel forces have besieged Arafat's compound on and off since last December, and Monday's action marked the third time this month to troops have surrounded his offices, which now consist of battered and scorched buildings that cover a full city block.
"The Israeli government, with these continuous attacks, has revealed to the whole world its real intentions," Arafat said in a statement issued by the Palestinian news agency Wafa. "Nothing can weaken our belief in our legal right to have our own independence and freedom, and all this Israeli aggression will not achieve any political results."
Arafat was inside the compound with security aides and was not harmed. The Israelis faced no real resistance as they moved into Ramallah, and have now taken over six of the eight main Palestinian cities and towns in the West Bank since launching the invasion last week.
The two West Bank areas that haven't been invaded are Jericho, which has been quiet during most of the 21 months of Mideast fighting, and Hebron, where the Israeli army maintains a permanent presence and arrested 10 Palestinians on Monday, most of them Hamas members.
Within an hour of moving into Ramallah and adjoining el-Bireh, Israeli soldiers announced on loudspeakers that a curfew had been imposed on the area's 200,000 residents, as in the other towns.
The army said it had taken up "strategic points" in Ramallah, was controlling access to the city, and had placed the area under curfew. Palestinians detonated explosives, slightly injuring one soldier, the army said. The streets were deserted except for Israeli jeep patrols.
The latest Israeli incursion came in response to a recent wave of Palestinian attacks.
"There's no doubt that with the current situation, it's hard to see how we can fight terror effectively without being in the Palestinian areas," Cabinet Secretary Gideon Saar told Israel Radio.
At least 600,000 Palestinians in the West Bank are confined to their homes by the curfews, although restrictions were temporarily lifted in two places, Nablus and Qalqiliya, so residents could shop and go to school.
The Palestinian leadership accused Israel of using the invasion as a pretext for getting rid of the Palestinian Authority and putting an Israeli military administration in its place.
"This is not a temporary step. It is a comprehensive and long-term Israeli plan that aims to destroy the future of the Palestinian people and the destiny of peace and security in the region," the statement said.
Israeli officials have denied the charge. An Israeli military administration presided over Palestinians until creation of the Palestinian Authority in 1994.
Meanwhile, Hamas renewed its threats against Israel and warned Arafat to lift the house arrest order against Yassin, the group's leader.
"We emphasize our right to continue the jihad (holy war) and resistance, and to intensify the martyrdom operations as a reaction to the policy of the occupation and the (Palestinian) authority," Hamas said in a statement.
In Jenin, Israeli troops carried out house-to-house searches, arresting the head of Palestinian military intelligence, Mohammed Abu Hanana, and his bodyguard, Palestinian security officials said. Troops also found two explosives laboratories and blew them up in Jenin.