The Palestinians, meanwhile, said truce talks between Israeli Foreign Minister Shimon Peres and Palestinian leader Yasser Arafat would not be held Tuesday evening as initially envisioned because of the Israeli incursion into Jenin and continued disagreement over the venue.
"There was no agreement on the venue and it looks like the meeting will have to wait another few days," said Nabil Abu Rdainah, senior adviser to Arafat.
Arafat said that "despite the continuous military escalation, the siege, our people are steadfast ... and we will not kneel before anyone, except before God in prayer."
Even if the two leaders do hold the first of at least three planned meetings, hopes are slim of a breakthrough to end nearly a year of bloodshed that has killed more than 700 people.
Also Tuesday, Palestinian gunmen killed two Israeli border police officers sitting at the entrance to their base in Israel, on the edge of the West Bank, police said. Later in the day, an Israeli telephone company employee was lightly injured in a shooting ambush at the entrance to an industrial zone in the West Bank.
The Jenin incursion began sometime after midnight Tuesday when Israeli tanks entered open fields around the town of 50,000 in the northern West Bank.
Palestinian witnesses said about two dozen Israeli tanks took up positions outside Jenin and an adjacent refugee camp, advancing to the first row of buildings.
Dozens of gunmen fired at the Israelis, drawing return fire, including several tank shells, witnesses said. Seven Palestinians were wounded, doctors said.
The army confirmed that troops were operating in Palestinian territory. It said soldiers fired small arms and one tank shell.
Arafat called his security chief in Jenin early Tuesday and asked residents there to show "steadfastness and tenacity in the face of this aggression," Palestinian officials said.
In nearly a year of fighting, Israeli troops have repeatedly entered Palestinian territory, but usually pulled out quickly. The incursion near Jenin marked the fourth time that Israeli forces remained in position for more than just a few hours.
Israeli military commentator Zeev Schiff, writing in the Haaretz daily, suggested that the incursion "won't be so quick to end," as Israel is intensifying its response to attacks by Palestinian militants.
A month ago, Israeli troops entered Jenin and demolished the main security building, but pulled out after several hours. At the time, Israeli security officials said Jenin had turned into a stronghold for Palestinian militants.
Israeli Defense Ministry spokesman Yarden Vatikay said, when asked about the duration of the Tuesday's incursion: "have no answer because all we care about is ensuring that terrorists do not come out of Jenin."
The Israeli government said dozens of suicide and car bombings as well as shooting attacks on Israelis have been launched from Jenin.
On Sunday, an Israeli Arab man blew himself up near a train station in the northern Israeli town of Nahariya, killing himself and three Israeli Jews. The Islamic militant group Hamas in Jenin announced Monday that it had sent the assailant.
Israeli officials have said they demanded that the Palestinian Authority arrest the bomber while he was still in Jenin, but to no avail.
Since the violence erupted last September, 611 people have been killed on the Palestinian side and 172 on the Israeli side.
The Peres-Arafat talks would be aimed at stopping the violence, but both sides said at least three meetings would be needed. Even if the two men can settle their disagreements over the venue Peres wants the Erez crossing near Gaza, Arafat prefers Egypt expectations are low.
U.S. Secretary of State Colin Powell, en route to a ministerial meeting of the Organisation of American States in Lima, Peru, said the Peres-Arafat talks would be pointless unless new proposals were put on the table.
"There is no point in having a meeting unless groundwork has been laid, unless people are coming to this meeting with specific ideas and not just...charges to go back and forth," said Powell.
Earlier truce agreements have not held up and the Palestinians suspect Peres has only a limited mandate from Israeli Prime Minister Ariel Sharon who remains distrustful of Arafat's intentions.
Palestinian Planning Minister Nabil Shaath said Tuesday that Peres and Arafat would not meet later in the day because of disagreements over the venue. "What happened last night and today will delay things for a couple of days, but will not cancel the meeting," Shaath added, referring to the Jenin incursion.
Arafat plans to meet Wednesday with Syrian President Bashar Assad, who staunchly opposes Israeli-Palestinian peace talks. Arafat, who is eager to mend his strained relationship with the Syrians, might have been reluctant to hold high-profile talks with Peres just hours before flying to Damascus.
In other developments Tuesday, Israeli police and soldiers closed Palestinian intelligence and security offices in Azariyeh, a West Bank town just outside Jerusalem, Israel radio reported. Also, Israeli forces barricaded the Democratic Front office in nearby Abu Dis, another West Bank suburb of Jerusalem.
Israel closed the offices because Palestinian security is implicated in sending attackers into Israel, Israel radio said.
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