JERUSALEM — Israeli and Palestinian teams are heading to Washington for preliminary talks toward a formal re-opening of negotiations after years of stalemate, but both sides are emphasizing that many obstacles stand between them and a final deal.

Israel's chief negotiator Tzipi Livni said early Monday as she left for Washington that talks will be complex and that she was leaving "cautiously but also with hope."

Palestinian negotiators also departed after the Israeli Cabinet cleared the way for talks on Sunday by acceding to Palestinian demands and agreeing to release 104 Palestinian prisoners convicted of deadly attacks.

The U.S. later announced the resumption of talks, the result of months of effort by U.S. Secretary of State John Kerry to get the sides back to the table.