BEIRUT (Reuters) -  Israel and Lebanon held “productive” talks over their disputed Mediterranean Sea border on Thursday and agreed to meet again next month, the United Nations and the United States said. Thursday’s meeting was the third this month between the longtime foes, mediated by the United States and hosted by the United Nations at a base in southern Lebanon. The meetings are the culmination of three years of diplomacy by Washington, and follow a series of deals under which three Arab nations - the United Arab Emirates, Bahrain and Sudan - agreed to establish full relations with Israel.