Israeli officials say the prisoners were being held because they posed a risk to the country's security. The Palestinian leadership says they were being held as political prisoners.

Their release was one of the demands made by Palestinian Prime Minister Mahmoud Abbas during recent talks with his Israeli counterpart, Ariel Sharon.

Both men will travel Wednesday to Jordan for a three-way summit with President Bush at the Red Sea resort of Aqaba, aimed at promoting the Roadmap to peace.

The plan calls for the end of the Israeli-Palestinian conflict and the establishment of an independent Palestinian state by 2005.

Among those released Monday was Tayseer Khaled, a senior member of the Democratic Front for the Liberation of Palestine.

Immediately after his release, he met with Palestinian President Yasser Arafat at his headquarters in the West Bank city of Ramallah. Mr. Arafat has not been invited to Wednesday's summit. Israel and the United States say they have broken off contacts with him and instead recognize the leadership of Mr. Abbas.

Following a recent meeting between Mr. Sharon and Mr. Abbas, Israel also agreed to release Ahmad Jubarah, 68, who is both the oldest and longest-held Palestinian prisoner.

He has served for nearly three decades behind bars after being convicted in for his role in a 1975 bomb attack in Jerusalem that killed 13 people and wounded 13 others. The Israeli prison service said it plans to release him this week.