NAQOURA, Lebanon (Reuters) - Israel and Lebanon on Wednesday held a second round of U.S.-mediated talks over their disputed sea border that has held up hydrocarbon exploration in the potentially gas-rich area, though sources said gaps between the sides remain large. Delegations from the long-time foes reconvened at a U.N. peacekeeper base to try to reach agreement over their maritime border after an initial meeting earlier this month. The sides presented contrasting maps on Wednesday outlining proposed borders that actually increased the size of the disputed area, sources said. The Lebanese proposal, which had been carried by local media for days prior to the talks, extended farther south than the border Lebanon had years before presented to the United Nations, according to a Lebanese security source.