Israeli officials say they have postponed the release of about 30 Palestinian prisoners who were set to be freed into Gaza on Monday.
Jailers were to bring the prisoners to the Erez crossing, to Gaza, but instead they are holding the detainees at a desert prison.
Israeli officials say President Shimon Peres must sign the prisoners' pardons before they can be released from custody. No explanation was given for the delay in authorizing the pardons.
But, Israel did free 57 other Palestinian prisoners to the West Bank on Monday.
In total, nearly 90 detained members of Palestinian President Mahmoud Abbas' Fatah faction were processed for release on Monday.
They are being freed as a goodwill gesture to Mr. Abbas before he meets Wednesday with Israeli Prime Minister Ehud Olmert to discuss an upcoming Mideast peace conference.
A senior Fatah official in the West Bank, Hussein al-Sheikh, said Israel should free 11,000 other jailed Palestinians.
Wednesday's meeting will be the sixth for the Mr. Abbas and Mr. Olmert in recent months.
Israeli officials say Mr. Olmert will host Mr. Abbas at the prime minister's Jerusalem home.
They are set to discuss a joint statement to be issued at a U.S.-sponsored conference, scheduled for November.
At their last meeting, on September 10th, the men established negotiating teams to work on the statement's wording.
But Mr. Abbas repeated a call Sunday for the conference to have a clear agenda that tackles the status of Jerusalem, Palestinian refugees and final borders. Mr. Olmert has said he wants a more general declaration of principles.
President Bush has said he hopes the conference will start a full resumption of peace talks leading to the creation of a Palestinian state alongside Israel.
Some information for this report was provided by AFP and AP.