Lebanese Foreign Minister Ali Shami in a letter to the United Nations this week called on the global body to put pressure in Israel to prevent the country from tapping into oil and natural gas reserves in the Mediterranean Sea.
Andrea Tenenti, a spokeswoman for the U.N. Interim Force in Lebanon, said while Israel unilaterally demarcated much of the maritime border, the peacekeeping mission didn't have the authority to intervene.
"The (border) line has not been recognized by the Lebanese government and we don't have a mandate to monitor the line," the spokesman told Lebanon's Daily Star newspaper. "A maritime boundary in that area was never established."
The UNIFL mandate is limited, officials said, to helping the Lebanese military prevent unauthorized arms shipments or other contraband from crossing the border.
Noble Energy announced a "significant" gas discovery last week at the Leviathan field about 80 miles off the coast of Haifa in the deep waters of the Mediterranean Sea.
"The results from the well confirm the pre-drill estimated resource range, with a gross mean for Leviathan of 16 trillion cubic feet," the company announced.
Lebanon contends that a portion of Leviathan lies within its maritime borders.
Hezbollah has told Israel not to touch its resources, spurring threats of retaliation from the Israelis.