JERUSALEM — Israeli and Lebanese leaders appear to have agreed to a U.S.-brokered deal that will let both countries exploit gas fields in the eastern Mediterranean, potentially ending a decades-long dispute over their maritime border, easing growing military tensions and providing a desperately needed source of income to Lebanon's collapsing economy.

The agreement, which needs formal approval in both countries, was hailed by leaders in Beirut and Jerusalem as a historic breakthrough. It is the first agreement on border demarcation between the two nations.

"This is an historic achievement that will strengthen Israel's security, inject billions into Israel's economy, and ensure the stability of our northern border," Israeli Prime Minister Yair Lapid said in a statement Tuesday.

Lebanese leaders have yet to make an official announcement on the deal, but President Michel Aoun said in a tweet Tuesday that "the final version of the offer is satisfactory for Lebanon and answers its demands and preserves its rights to its natural wealth." Later, he tweeted that he had received a phone call from President Biden "in which he congratulated [Aoun] on the conclusion of the negotiations."

"If everything goes well, [Washington's] efforts could imminently lead to a historic deal," Elias Bou Saab, Lebanon's lead negotiator on the issue and deputy parliament speaker, told Reuters after receiving the text of the deal from American officials Tuesday.

Officials hope the agreement, if finalized, will cool intensifying tensions along the frontier. Hezbollah, the Iran-allied militant group that controls southern Lebanon, has threatened to attack a new offshore gas facility that Israel is readying for production in what Lebanon claims are disputed waters. The group has launched drones toward the gas field more than once, including three unmanned aircraft that were shot down by Israel in early July.

In the face of Hezbollah's threats to strike should Israel begin pumping natural gas from the Karish Field, Defense Minister Benny Gantz put troops on high alert after the maritime border talks ran into last-minute disputes last week.

Hezbollah, which along with its allies, holds the largest bloc in parliament, had no immediate comment on the draft of the agreement. A media officer for the group told The Washington Post that Hezbollah leader Hasan Nasrallah is likely to talk about the deal in a speech scheduled for Tuesday. "Today we'll find out," the official said.

The agreement would define only the offshore boundary between the sworn enemies, not the 50-mile land border that remains in dispute after multiple wars and continues to be patrolled by a United Nations monitoring force after more than four decades.

The maritime frontier has proved to be equally contentious in recent years, particularly after gas deposits were discovered in the sea bed inside the 330-square mile region. Israel, which has already developed gas fields in nearby waters, strung a line of buoys three miles out from a rocky cliff near the U.N. headquarters. Beirut condemned the move as a unilateral provocation.

Resolving the dispute — which has gained urgency as the risk of conflict rose and Lebanon's economic free fall has grown more critical — has been a regional priority for the Biden administration. The president's special envoy, Amos Hochstein, brokered talks over the past year with the goal of giving countries fair access to the area.

The deal comes as gas discoveries are remaking the energy map of the Mediterranean just as Europe is looking for alternate sources in the wake of Russia's invasion of Ukraine. Gas diplomacy may also be thawing Israel's tense relationship with Turkey, for example, as the two countries seek to revive long-abandoned plans for a pipeline through Turkey to Europe.

Details of the agreement were not made public Tuesday. But reports of its broad terms in recent week weeks suggest that it clarifies the lines of exclusive economic zones for both countries. Lebanon would gain access to promising fields in previously disputed waters; Israel would be free to begin operating the Karish well with Lebanon's agreement.

Lebanese officials have said the final deal would not have them in direct partnership with Israel, and it was unclear how royalties would be split from the one area, the Qana Field, which lies partially in Israeli waters.

Lebanon in 2017 issued licenses to move forward with offshore oil and gas development for two of the 10 blocks in the Mediterranean, including Qana, and officials were moving quickly to advance the process.

Lebanese Prime Minister Najib Mikati met Tuesday morning with Energy Minister Walid Fayyad and a delegation from French oil giant Total. Fayyad expressed hope that the deal will benefit Lebanon and grant it its "rights and full share in Qana Field without sharing it with anyone," according to state media. He also emphasized the need to begin exploration and development, which often take years, as soon as possible.

"Logistical issues take time but work will begin immediately," he said.

Lebanon's leaders and public hope the deal will pave the way for gas exploration and bring in much-needed revenue to the country, which has been hit by sharp economic decline and a banking crisis that have ravaged the local currency and left much of the country out of work.

In a place previously an oasis for opulence, people sifting through trash cans for food is now a common sight in the capital Beirut. The World Food Program said in a report last month that an estimated 33 percent of Lebanese now lack minimum dietary provisions.

Access to gas fields could mean export revenue and energy sources for a country where electricity is now an expensive luxury and some Lebanese have begun joining Syrians and other migrants in perilous boat journeys to Europe.

Israel hopes access to the gas deposits will help pull Lebanon back from the brink of collapse and reduce the risk of another all out war.

"Such a field would weaken Lebanese dependency on Iran, restrain Hezbollah and bring regional stability," Lapid told his cabinet earlier this month.

In Israel, which does not have diplomatic relations with Lebanon, it was unclear what steps the government needed to take to ratify the agreement. Legal experts said the deal could be enacted simply on the approval of the cabinet, most of whom have signaled enthusiasm for a draft they said benefits both countries. They pushed back on some right-wing lawmakers, including former prime minister Benjamin Netanyahu, who blasted the government for "surrendering" to Hezbollah.

But Israel is holding national elections in less than a month, and some officials, including alternate Prime Minister Naftali Bennett, have said in the past that such an important agreement should go before the Knesset, Israel's parliament.

Bennett, as Lapid's partner in the government, still holds an effective veto in the cabinet. His office said Tuesday that he will make a decision on the agreement after reading the draft and consulting with security officials.

Dadouch reported from Beirut.