NICOSIA, Cyprus (AP) — A United Nations envoy called off talks with the rival leaders of ethnically divided Cyprus on Friday after failing to find "common ground" on convening a final summit to aim for an overall reunification deal, but the U.N. said the years-long peace process had not collapsed. Two years of negotiations have made significant progress on how to share power in an envisioned federation, but they have stumbled on pivotal issues of post-reunification security arrangements and how much territory each side would administer. Greek Cypriots want all Turkish troops gone as part of any deal and propose an international police force to oversee security.