Israel and Lebanon resumed US-mediated talks on Wednesday over their disputed Mediterranean Sea border, Lebanon's state news agency reported. The talks aim to kick-start hydrocarbon exploration in the potentially gas-rich area. The longtime foes held three rounds of talks last month hosted by the UN at a peacekeeper base in southern Lebanon. The US and Office of the UN Special Co-ordinator for Lebanon said Wednesday's talks had been productive. "We remain hopeful that these negotiations will lead to a long-awaited resolution," a joint statement read. "The parties committed to continuing negotiations in early December." But sources said that significant gaps exist between the sides after each presented contrasting maps outlining proposed borders that actually increased the size of the disputed area. Israel already pumps gas from huge offshore fields but Lebanon, which has yet to find commercial gas reserves in its own waters, is desperate for cash from foreign donors as it faces the worst economic crisis since the 1975-1990 civil war. The meetings are the culmination of three years of diplomacy by Washington, and follow a series of deals under which the United Arab Emirates, Bahrain and Sudan agreed to establish full relations with Israel. Lebanon said the talks are strictly limited to their disputed boundary.