JERUSALEM -- Israel announced yesterday that it would curtail offensive operations against Palestinians in response to President Mahmoud Abbas´s efforts to halt attacks on the Jewish state, marking a significant step toward a full-scale cease-fire between the two sides.

The decision followed the deployment of Palestinian police yesterday in the central and southern parts of the Gaza Strip to deter militants who have frequently fired rockets and mortars at Israeli communities. Palestinian troops had taken up positions in northern Gaza and brought about a sharp drop in attacks.

But in a blow to Abbas, the Islamic extremist group Hamas celebrated a stunning victory in seven of 10 municipal elections in Gaza, thrashing the mainstream Fatah faction -- Abbas´s party -- and raising the profile of the Islamists as a political force.

Yesterday, after the Palestinian police deployment, the Israeli army said in a statement that it was cutting back offensive measures ´´in light of the ongoing cooperation between Israel and representatives of the Palestinian Authority." It said ´´proactive operations" would be minimized in the West Bank and halted altogether in areas of Gaza where Palestinian police are deployed.

The statement also said the ´´targeting of terrorists," a reference to Israel´s policy of killing fugitives in pinpoint air and ground strikes, would take place ´´only if there is an immediate threat" and only with the explicit authorization of the army chief, Lieutenant General Moshe Yaalon.

Israel also said that by next week it would reopen all border crossings in Gaza that were closed after Palestinians attacked the Karni checkpoint on Jan. 13, killing six Israelis. Israel also pledged to ease travel restrictions in the West Bank.

The decisions appear to meet some of the demands put forward by armed Palestinian groups as their price for a long-term truce, which Abbas has been trying to orchestrate since his election on Jan. 9. Most of the groups had been informally honoring Abbas´s request last week for a monthlong, unilateral cease-fire.

Israeli officials said other measures, including a timetable for the withdrawal of Israeli troops from West Bank towns, would be discussed at a summit between Abbas and Prime Minister Ariel Sharon, expected to be held next week.

Diplomacy between the two sides is surging, in contrast to years of estrangement. Israel´s defense minister, Shaul Mofaz, is scheduled to meet this weekend with Mohammad Dahlan, a security adviser to Abbas. Shimon Peres, a member of Sharon´s Cabinet, held talks with Palestinian Finance Minister Salam Fayyad yesterday on the sidelines of the World Economic Forum in Davos, Switzerland.

´´It´s the first time I can recall that someone has taken on leadership and in a few days changed the whole atmosphere in the Middle East," Peres said in Davos yesterday, referring to Abbas.

Abbas succeeded Yasser Arafat after his death last November, inheriting a 4½-year-old insurgency in the West Bank and Gaza Strip that has killed thousands and ravaged the Palestinian economy.

His endeavor to end the armed uprising is opposed mainly -- though not solely -- by Hamas, an Islamic opposition group that has ventured in the past month into the political arena for the first time, sponsoring local candidate slates in a series of municipal elections.

In Thursday´s voting in 10 local councils, the group won 75 of the 118 council seats up for grabs, compared to 39 for Fatah. The results surprised most analysts, who had predicted that Hamas would claim only about 35 seats.

Thousands of Hamas supporters marched in Gaza City yesterday carrying the group´s signature green flag, while loudspeakers blared with the slogan, ´´Hamas´s victory proves Islam is the solution." Spokesmen for the group, which rejects Israel´s right to exist and is listed as a terrorist organization by the United States, attributed the showing to the hard line Hamas takes against the Jewish state and to the popularity of its suicide attacks that have killed hundreds of Israelis.

´´Our people have a consensus on the choice of jihad and resistance, and the election has underscored that concept," a Hamas spokesman, Muhir al-Masri, said in Gaza.

Analysts said Hamas´s victory had more to do with the anger felt by Palestinians toward alleged corruption in the Fatah-run Palestinian Authority.

´´It shows clearly that the people will hold the authority accountable when it fails or engages in corruption," said Hassan Kashef, a political analyst in Gaza. He said the results would force Abbas to shake up Fatah before parliamentary elections this summer or face the possibility of the party being overtaken by Hamas.

Fatah, the main faction of the Palestine Liberation Organization, has dominated Palestinian politics for more than 40 years. But its leaders have been dogged by allegations that they have stolen or mismanaged millions in foreign aid money since Arafat set up his administration in the West Bank and Gaza a decade ago.

Hamas, by contrast, hands out money to thousands of needy Palestinians through charities it runs across the West Bank and Gaza. The group is largely perceived by Palestinians as untainted by government corruption.

´´Hamas succeeded by choosing the right candidates -- people who are technocrats and have experience in work," said Ahmed Al-Kurd, who heads a Hamas charity in the Gaza Strip town of Deir Al-Balah and was elected Thursday to be its next mayor.

The 56-year-old schoolteacher said in an interview that most residents of his town were eager to see the municipality overhauled after a decade under Fatah´s administration. (Copyright 2005 The New York Times Company 01/29/05)