Israel was scheduled to release 550 prisoners Sunday, in the second stage of an exchange with Hamas in Gaza.
In the first stage in mid-October, Israel released 477 Palestinian militants, many serving multiple life sentences, in return for Gilad Shalit, the Israeli soldier held hostage by the Islamist movement ruling Gaza for more than five years.
The prisoners scheduled to go free Sunday are considered less hardcore and include no one serving a life term. Most are members of the armed wing of Palestinian President Mahmoud Abbas' Fatah movement.
The vast majority are to go to the West Bank and had been already taken to an Israeli military base near Ramallah, on the central West Bank, from where they were scheduled to cross over into Palestinian autonomous territory in the evening.
About 40 of the prisoners had been transported to the Kerem Shalom crossing to the Gaza Strip. Two others were from East Jerusalem and two from Jordan were to cross the Allenby Bridge border with Israel's eastern neighbor.
Israel's Highest Court of Justice late Saturday rejected petitions against the release, filed by relatives of Israelis killed in attacks by Palestinian militants, Israel Radio reported.
The court ruled that the issue had political and security ramifications and therefore was a government decision in which the court would not intervene.
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