The United States and 10 of its allies called Wednesday for a 21-day ceasefire across the Israel-Lebanon border as they work to prevent a regional war from erupting.

The “immediate” ceasefire across the border would “provide space for diplomacy towards the conclusion of a diplomatic settlement,” a statement from the countries read.

“The situation between Lebanon and Israel since October 8th, 2023 is intolerable and presents an unacceptable risk of a broader regional escalation. This is in nobody’s interest, neither of the people of Israel nor of the people of Lebanon,” read the statement from the United States, Australia, Canada, European Union, France, Germany, Italy, Japan, Saudi Arabia, United Arab Emirates and Qatar.

“It is time to conclude a diplomatic settlement that enables civilians on both sides of the border to return to their homes in safety,” the countries said. “Diplomacy however cannot succeed amid an escalation of this conflict.”

“We call on all parties, including the Governments of Israel and Lebanon, to endorse the temporary ceasefire immediately,” the statement read, citing a UN Security Council resolution calling for a cessation of hostilities between Israel and Hezbollah.

“We are then prepared to fully support all diplomatic efforts to conclude an agreement between Lebanon and Israel within this period, building on efforts over the last months, that ends this crisis altogether,” the statement went on.

US President Joe Biden and French President Emmanuel Macron issued a separate statement saying it was time “to give diplomacy a chance to succeed and avoid further escalations across the border.”

“It is time for a settlement on the Israel-Lebanon border that ensures safety and security to enable civilians to return to their homes,” the American and French presidents said late Wednesday after urgent discussions on the margins of the United Nations General Assembly in New York.

“The exchange of fire since October 7th, and in particular over the past two weeks, threatens a much broader conflict, and harm to civilians,” the presidents wrote. “We therefore have worked together in recent days on a joint call for a temporary ceasefire to give diplomacy a chance to succeed and avoid further escalations across the border.”

Biden and Macron called “for broad endorsement and for the immediate support of the Governments of Israel and Lebanon.”

CNN reported earlier Wednesday that the United States was working urgently on a plan to mediate a ceasefire, according to three sources familiar with the matter, as officials eye with deepening concern the prospects of a widening conflict.

American officials have been working with counterparts from France and other nations to try and reach a diplomatic agreement that would pause fighting along Israel’s northern border while also resuming ceasefire and hostage talks for Gaza, the people said.

French Foreign Minister Jean-Noel Barrot told the United Nations Security Council Wednesday night that France has been working with the US to secure a 21-day ceasefire to allow negotiations and that details would be made public soon. “A diplomatic solution is indeed possible,” he said, adding that he would travel to Beirut at the end of the week to work with local stakeholders.

A source said that the effort to mediate a ceasefire began in earnest for the Biden administration after President Joe Biden’s national security adviser, Jake Sullivan, spoke on the phone with top Israeli official Ron Dermer on Monday.

Biden has been discussing the escalating hostilities in the Middle East with various world leaders this week on the sidelines of the General Assembly. On Wednesday, he discussed the matter with Macron, the White House said

The efforts come as Israel’s top general said Wednesday that the Israeli military is preparing for a possible ground incursion into Lebanon.

Israel’s Prime Minister Benjamin Netanyahu has given the green light for his government to engage with the US efforts, an Israeli official told CNN.

The official said that Netanyahu gave his approval with the understanding that any agreement would have to allow for the return of Israeli civilians to their homes in northern Israel.

Amos Hochstein, a senior White House adviser, is involved, the source said, adding that the Americans are not talking to Hezbollah directly.

Secretary of State Antony Blinken has spent the past few days on the sidelines of the UN gathering shuttling back and forth between Arab and European partners working on the details of a proposal to stop the fighting between Israel and Lebanese Hezbollah, a senior State Department official said.

On Monday night, a US official told CNN that the administration was extremely close to finalizing a plan to deescalate tensions between Israel and Hezbollah and Hamas, but that officials were trying to keep the negotiations as private as possible to avoid upending the fragile talks involving multiple countries.

But a focus now, officials say, is to de-couple the ceasefire efforts for Lebanon and for Gaza. Hezbollah has long said they would only stop their rocket fire when there was quiet in Gaza while Israel has tried to treat them as separate conflicts. The White House has also consistently argued that a ceasefire in Gaza would unlock much more, including a diplomatic deal with Hezbollah that would allow Lebanese and Israeli civilians to return home.

Given the fear of escalation, American and other international officials are pushing for a deal first to end the skyrocketing Lebanon fighting so that they can then turn back to the Gaza ceasefire efforts that have been stuck.

Biden and his top national security officials have regularly expressed optimism and hope that deals for both were close at hand, only to see them fall apart. Recently, US officials have said they don’t know whether Netanyahu or Hamas leader Yahya Sinwar have the political willingness to agree to a ceasefire in Gaza.

A European diplomat expressed skepticism about the prospects of the efforts succeeding, saying they see “no reason to be optimistic right now.” The diplomat added that ongoing talks are pushing ahead but the “situation is deteriorating and escalating by the hour.”

The plans could be a focus of conversation at an emergency meeting of the UN Security Council scheduled for later Wednesday that France called for.

At a separate UN Security Council meeting earlier Wednesday, British Prime Minister Keir Starmer called for “an immediate ceasefire between Israel and Lebanese Hezbollah and the implementation of a political plan, which allows Israeli and Lebanese civilians to return to their homes and live in peace and security.”

A British official stressed it is time to move beyond calls for “de-escalation” and instead call for an immediate stop to the fighting. That official also suggested the diplomatic efforts on a ceasefire in Gaza should be delinked from the efforts on Lebanon in order to achieve an immediate ceasefire across the blue line.

Speaking on ABC’s daytime talk show “The View,” Biden alluded to ongoing talks to reach a ceasefire in Lebanon that would unlock further peace discussions elsewhere in the region.

“There’s a way to do it, and they have a possibility – I don’t want to exaggerate it, but a possibility — if we can deal with a ceasefire in Lebanon, that it can move into dealing with the West Bank, but we also have Gaza to deal with,” he said.

“But it’s possible,” he said, “and I’m using every bit of energy I have with my team … to get this done. There’s a desire to see change in the region.”

Blinken said in interviews Wednesday the US is working toward a plan that would allow displaced Israeli and Lebanese citizens to return to their homes.

“It would be through a diplomatic agreement that has forces pulled back from the border, create a secure environment, people return home. That’s what we’re driving toward. Because while there’s a very legitimate issue here, we don’t think that war is the solution,” he told NBC News.

This story has been updated with additional developments.