U.N. Secretary-General Ban Ki-moon said Thursday he was "deeply troubled" by continued Israeli settlement building, warning that the practice will ultimately prevent the establishment of a Palestinian state. Israeli settlement construction in East Jerusalem and the occupied West Bank is "deepening the Palestinian people's mistrust in the seriousness on the Israeli side toward achieving peace," Ban said at a Ramallah news conference Thursday with Palestinian Authority President Mahmoud Abbas. A day earlier, Israelis and Palestinians launched formal talks on the terms of a two-state solution after a five-year freeze. The talks were overshadowed by recent Israeli announcements on promoting plans for more than 3,000 new settlement apartments. In Ramallah, Ban also participated in a Model U.N. event, with a video link to Gaza. He will attend a similar Israeli event on Friday.