Updated

A former Palestinian negotiator with Israel says wide gaps make a peace deal impossible.

Mohammed Ishtayeh, a senior aide to Palestinian President Mahmoud Abbas, also says he believes U.S. mediation is "unbalanced" in favor of Israel and that other world powers must join the talks.

Ishtayeh said he was expressing his personal views. He said late Tuesday he quit the Palestinian team a month ago over accelerated Israeli settlement construction.

U.S. Secretary of State John Kerry was to return to the region Wednesday to try to salvage the troubled talks.

Ishtayeh said that his sense is that Israel wants to annex large parts of the West Bank, one of the occupied territories the Palestinians want for a state.

Ishtayeh says major differences "block any possibility of a peace deal."