The first group to be released comprises 57 prisoners from the West Bank. 30 natives of Gaza will subsequently be freed.
The daily Haaretz said the move is widely seen as an effort to bolster the government of Palestinian Authority Chairman Mahmoud Abbas, adding that procedural and legal questions may delay the release of the second group until at least Tuesday.
It said the hitch was apparently tied to questions over the status of the government in the Gaza Strip, controlled by Hamas since it overthrew Abbas' Fatah movement earlier this year.
The 87 prisoners are mostly members of Fatah, along with several who are members of smaller Palestinian factions. None belong to Hamas.
According to the Prisons Service, Israel is holding around 11,000 Palestinian prisoners.
