The Israeli and Palestinian leaders were invited by Egyptian President Hosni Mubarak, whose aides are also trying to mediate a cease-fire among Palestinian militant groups. The meeting, to be held in the Red Sea resort of Sharm el-Sheikh, also marks the steadily warming contacts between Israel and Egypt.
Israel's state television reported last night that Mubarak would announce the return of Egypt's ambassador to Israel, after an absence of 4 1/2 years. Egyptian officials neither confirmed nor denied the report.
Mubarak had until now refused to meet Sharon since he became prime minister in 2001, to protest Israel's military response to the Palestinian uprising.
Sharon and Abbas had tentatively planned to meet next week in Jerusalem, but their aides were bickering over the scope of the talks. Israel wanted to limit discussions to security issues, especially related to its planned withdrawal from the Gaza Strip in July; the Palestinians wanted a bigger agenda including broader political agreements.
Those differences still exist, but Egypt's surprise invitation made it difficult for either Sharon or Abbas to back out. They also know that U.S. Secretary of State Condoleezza Rice is scheduled to arrive in the region at the end of this week and could alter her itinerary to attend the meeting on Tuesday.
The Palestinian prime minister, Ahmed Qureia, said yesterday that Abbas, widely known as Abu Mazen, will ask Sharon to release Palestinian prisoners and withdraw Israeli troops to the lines held before the uprising broke out in September 2000, in exchange for a cease-fire by militant groups.
"We shall work seriously and with vigor for a mutual cease-fire to which Israel, too, will be connected," Qureia said. Israeli officials have rejected the idea of signing formal agreements with militants.
Jabril Rajoub, a senior Palestinian security official, said the summit could be the means to end the violent uprising. "We want an opportunity to disengage from this cycle of blood," he said at a news conference. "We hope that Sharon understands that both sides need to bring this struggle to an end, bring us to a peace process and a historical reconciliation."
Mark Regev, a spokesman for Israel's Foreign Ministry, said the summit's importance depended on whether it improved security for both sides.
"This is not a point for a mere photo op," Regev said. "We don't want to rush to a meeting until there can be tangible benefits for both sides. The process is going good and the momentum is positive. But it is still fragile. The Palestinians started well on combating terrorism but we are worried that what Abu Mazen is doing is only a temporary fix."
Egypt's intervention is part of the country's renewed involvement in the peace process. In December, Mubarak offered rare praise for Sharon, saying, "It is difficult to make progress these days, but this prime minister can move on the path of peace and produce a solution if he wants it."
Egypt is especially focused on ensuring calm in Gaza after an Israeli withdrawal. Yesterday, Egyptian officials continued their talks with Gaza militants, who want assurances that Israel will refrain from military actions in exchange for the miltants disarming.
Sharon and Abbas last met in June 2003, when Abbas was Palestinian prime minister. Abbas resigned a few months later after disputes with the Palestinian leader Yasser Arafat.
After Arafat's death in November, Abbas won election as his successor, as president of the Palestinian Authority. With Israel's approval, he has deployed thousands of Palestinian police in Gaza to restore order and to prevent militants from launching attacks.
Israeli and Palestinians security chiefs are scheduled to meet today for the third time this week to discuss Israeli troops withdrawing from four or five Palestinian cities in the West Bank and turning over security to Palestinian authorities.