President Biden on Tuesday hailed an agreement to end the maritime dispute between Israel and Lebanon as a "historic breakthrough."

Driving the news: Israeli and Lebanon earlier Tuesday announced they had accepted a U.S.-mediated agreement on the maritime border between the two traditional enemies.

• Once signed, the deal will allow the beginning of natural gas exploration in the disputed area — a potentially gas-rich, 330-square-mile area with an estimated value reaching billions of dollars — in the eastern Mediterranean Sea and reduce the threat of regional war. 

What he's saying: "Energy—particularly in the Eastern Mediterranean—should serve as the tool for cooperation, stability, security, and prosperity, not for conflict," Biden said in a statement.

• The agreement "will provide for the development of energy fields for the benefit of both countries, setting the stage for a more stable and prosperous region, and harnessing vital new energy resources for the world," he added.
• "It is now critical that all parties uphold their commitments and work towards implementation."

Biden said he spoke to Israeli Prime Minister Yair Lapid and Lebanese President Michael Aoun separately on Tuesday to congratulate their governments on the agreement.

• "This agreement also protects Israel’s security and economic interests critical to promoting its regional integration. It provides Lebanon the space to begin its own exploitation of energy resources," the U.S. president said.

The big picture: U.S. envoy Amos Hochstein in the past year resumed efforts to reach a deal after efforts by previous officials over the last decade failed.

• A week ago, it appeared the two sides were headed toward a deal. But negotiations broke down after Israeli officials rejected comments by their Lebanese counterparts on the draft agreement, claiming they were a "material breach" of the text.
• Israeli officials were concerned about Lebanon's refusal to recognize the three-mile security line of buoys Israel placed in the sea between the countries, and the Lebanese reservations about the compensation Israel would get for its economic rights in the disputed area
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  • But U.S. officials continued to mediate between the parties and after "a very intensive last several days and very long nights, the governments of Israel and Lebanon agreed, individually and separately agreed, with the United States to end this dispute," a senior Biden administration official told reporters Tuesday.

• Details: Israeli sources involved in the negotiations said in a briefing with reporters that the Biden administration gave Israel a letter of guarantee for the agreement.

  • The letter clarifies that the U.S. is committed to the security and economic rights of Israel in a scenario in which Hezbollah, which had threatened war if Lebanon's economic rights weren't respected, or another group decides to challenge the signed agreement, the sources said.
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