* Says 11,000 Palestinians forced to quit E.Jerusalem since 1996 * Casts doubt on progress in U.S.-brokered peace process By Stephanie Nebehay GENEVA, March 21 (Reuters) - A U.N. human rights investigator accused Israel on Friday of "ethnic cleansing" in pushing Palestinians out of East Jerusalem and cast doubt that the Israeli government could accept a Palestinian state in the current climate. He spoke against a backdrop of deadlocked peace talks and accelerating Israeli settlement expansion in the occupied West Bank and East Jerusalem which Palestinians say is dimming their hope of establishing a viable state on contiguous territory.