TEL AVIV—Israel and Palestinian prisoner leaders sealed an Egyptian- brokered deal to end a weekslong hunger strike by about 2,000 imprisoned Palestinians, which had stirred local and international concern about a flare-up of unrest if one of the prisoners were to die.

In return for the end to the hunger strike, Israel agreed to improve the conditions of the Palestinians´ imprisonment and release a handful of prisoners held without charges in "administrative detention" at the end of their current terms, said Palestinian officials.

The prisoners, held at various jails around the country, committed to cease all "terrorist" activity from within the prison walls in return for Israel easing conditions of their incarceration. That activity includes aiding in the recruitment and financing of militant groups, Israel said.

It was the second time in about two months that Israel bowed to pressure from a hunger strike by Palestinian prisoners.

The deal also was the latest instance in which Egypt intervened to mediate between Israelis and Palestinians. At the end of 2011, Egypt helped secure the release of Sgt. Gilad Shalit. The Egyptian mediation—which was handled by its intelligence branch—comes as a vote for a new Egyptian president has increased uncertainty about the future of Israel-Egypt ties and their 33-year-old peace pact.

The Palestinians reached out to Egypt because a large portion of the hunger-striking prisoners are loyal to Hamas, the Islamic militant group that controls the Gaza Strip and doesn´t have relations with Israel.

"This is the new Egypt playing a constructive role, just as they played with Gilad Shalit, and that´s important to note," said Yossi Alpher, a former Israeli security official and the editor of Bitterlemons.org, an online Israeli-Palestinian forum.

Israel, the Palestinian Authority and the international community were concerned about several Palestinians who were in critical condition after fasting for about 10 weeks. This month, Robert Serry, the United Nations´ Mideast envoy, urged the sides to reach an agreement "before it is too late."

Israel feared Tuesday´s Palestinian observance of the "Naqba"—or catastrophe—marking the uprooting of Palestinians from their homes during the 1948 war that followed Israel´s declaration of independence, could fan protests.

The Palestinians won an Israeli commitment to end solitary confinement for some prisoners and to allow Gazan residents visit relatives inside Israeli jails.

Israel also reinstated access to higher education for prisoners after canceling the privilege in retaliation for Sgt. Shalit´s incarceration.

The strike highlighted Israel´s use of "administrative detention,´´ a decades-old practice that allows the military to hold prisoners considered security threats without bringing formal charges, and to keep extending their incarceration period.

Israeli officials said they feared the deaths of Thaer Halahleh and Bilal Diab, two Palestinian activists who had fasted for 77 days to protest administrative detention. At the beginning of March, Israel agreed to release Khader Adnan, an Islamic Jihad activist, at the end of his term.

A spokesman for Israeli Prime Minister Benjamin Netanyahu said the deal was meant as a gesture to Palestinian President Mahmoud Abbas to renew peace talks. Mr. Netanyahu over the weekend sent a letter to Mr. Abbas urging the immediate resumption of negotiations. (Copyright © Dow Jones & Company, Inc.) 05/15/12)