In the next few days Israel will submit to the United Nations its take on where its maritime economic border with Lebanon should be, as the two countries scramble for gas reserves estimated to be worth billions of dollars.

Israel's position is due to be approved by the cabinet on Sunday; Jerusalem argues that Lebanon's proposal includes major areas belonging to Israel.

Last August, Lebanon submitted to the United Nations its version of where the maritime border should be - the exclusive economic zone. In November, it submitted its version of its western border, with Cyprus.

The Lebanese proposal does not include the large Tamar and Leviathan gas prospects, operated by Delek Energy and U.S. company Noble Energy. But the National Infrastructure Ministry found that the proposal contains reserves with a potential value in the billions of dollars.

The Lebanese also sent their version to the United States, which conducted an expert review and endorsed the document. A senior Foreign Ministry official told Haaretz that the American diplomat in charge of the issue was Frederic Hof, who was responsible for Syria and Lebanon under the former U.S. special envoy to the Middle East, George Mitchell. Hof has kept the Israel-Lebanon brief despite Mitchell's resignation two months ago.

In April, Hof began shuttling between Beirut and Jerusalem. A senior administration official told Haaretz that Hof's main goal was to prevent the border from becoming a source of tension between Israel and Lebanon, which could give Hezbollah a pretext for targeting Israeli gas installations.

Beyond the political and diplomatic interest, the United States has an economic interest in keeping the parties calm, not least because American companies are involved in the search for gas an oil in Israel, Lebanon and Cyprus. Hof told his counterparts in Jerusalem that Israel should cooperate with setting the maritime border to prevent the creation of an "underwater Shaba Farms," referring to a contested area on the Israel-Lebanon border.

The Foreign Ministry official said Israel had asked the Americans to relay a warning to Lebanon on the matter. Foreign Ministry officials told Hof that Israel would not allow a provocation on the matter or an attack on Israeli gas installations. They said Israel would consider such an attack an attack on its sovereign territory and would retaliate "strongly" against Lebanon.

Hof responded by suggesting that Israel submit to the United Nations its own outlook on the border and try to launch a dialogue. Hof asked Israel not to turn the issue into a political spat but to see it as an economic and technical matter that could benefit all parties.

Israel rejected indirect talks via the United Nations, calling on Lebanon to begin negotiations on all border issues, not just the maritime border. The foreign and infrastructure ministries believe that Lebanon is claiming vast offshore territories that belong to Israel under international law.

"It's important to provide the UN with the Israeli version of the border as soon as possible, to react to Lebanon's unilateral move," a senior Foreign Ministry official told Haaretz. "Not responding could be interpreted as a tacit agreement. We must act fast to ensure Israel's economic rights in these areas."

Israel has become even more concerned about the positioning of the border after learning recently that a Norwegian company has begun searching for gas in the area. The search is due to be completed within months, and the Lebanese government hopes to use the findings to license international energy companies to probe areas that could be in Israel's exclusive economic zone.