World Bulletin / News Desk
It was not immediately clear who would replace Mladenov as the U.N. envoy to Iraq, U.N. officials and diplomats say.
Longtime Dutch diplomat Serry has held the top U.N. post for Israel and the Palestinian territories for more than eight years.
Mladenov comes to the job as U.S.-brokered peace talks have collapsed and amid increased tensions between the Israelis and Palestinians.
Last month, Ban said he is alarmed that Israelis and Palestinians appear to be engaged in a downward spiral of actions and counter actions and called on both sides not to make divisions worse.
Israel was withholding critical Palestinian tax revenue in retaliation for their moves to join the International Criminal Court (ICC) after a failed bid by the Palestinian Authority to secure statehood via a U.N. Security Council resolution.Israel and the United States both condemned the ICC move.
Momentum has built since President Mahmoud Abbas succeeded in a bid for de facto recognition of Palestinian statehood at the U.N. General Assembly in 2012, making Palestinians eligible for the ICC.