The U.S., the European Union and almost a dozen other countries called jointly on Wednesday for an immediate 21-day cease-fire to allow for negotiations between Israel and Hezbollah amid fears that their escalating conflict could plunge the broader region into an all-out war.

Israel and Hezbollah, which is based in Lebanon and backs fellow Iranian proxy group Hamas in its ongoing war with Israel, have been engaged in cross-border conflict since the war began with Hamas’s Oct. 7 terrorist attack on Israel, in which about 1,200 people were killed.

The violence further intensified in recent days with the deadly explosions of pagers and walkie-talkies across Lebanon, for which Hezbollah blamed Israel, followed by a wave of airstrikes by Israeli forces. More than 600 people in Lebanon have been killed and thousands of people in both countries have been displaced in the worst violence between them since 2006.

The situation between Israel and Lebanon “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,” the countries said in a joint statement. 

“It is time to conclude a diplomatic settlement that enables civilians on both sides of the border to return to their homes in safety,” they said, calling for immediate support from all parties, including the governments of Israel and Lebanon.

The proposal was negotiated and agreed to by the U.S., Australia, Canada, the E.U., France, Germany, Italy, Japan, Saudi Arabia, the United Arab Emirates, the United Kingdom and Qatar. It is unclear how Israel and Hezbollah will respond.

In addition to halting the violence between Israel and Hezbollah, officials say, a broader goal of the cease-fire is to jump-start stalled peace talks between Israel and Hamas in the Gaza Strip, where more than 41,000 Palestinians have been killed according to health officials and at least 97 people kidnapped by Hamas on Oct. 7 are still being held almost a year later.

“We’ll see if it opens up some possibilities on the Gaza side,” a senior Biden administration official told reporters, “because we do need to bring the hostages home, and we remain very focused on that.” 

In an appearance Wednesday on ABC’s “The View” before the cease-fire proposal was announced, President Joe Biden said “all-out war” was possible.

“But I think there’s also the opportunity — we’re still in play to have a settlement that could fundamentally change the whole region,” he said.

Shuttle diplomacy

On the sidelines of the United Nations General Assembly this week in New York, Secretary of State Antony Blinken shuttled back and forth among Arab and European countries working on the details of the proposal, a senior State Department official told NBC News. 

Blinken first rolled out the broad outlines of the plan Monday evening at a meeting of foreign ministers from the Group of Seven nations, the official said, asking them to refrain from pursuing any other measures in the meantime. 

On Wednesday, in a meeting with top diplomats from Gulf Arab nations, Blinken stepped outside with Mohammed bin Abdulrahman Al Thani, the prime minister and foreign affairs minister of Qatar, to secure his country’s support. At the end of the meeting, the official said, Blinken approached Faisal bin Farhan Al Saud, the foreign minister of Saudi Arabia, to ask that the kingdom also sign on to the agreement. 

Speaking ahead of the meeting with Gulf Arab diplomats, Blinken had warned that the “risk of escalation in the region is acute.”

Meanwhile, Blinken’s deputy chief of staff, Tom Sullivan, met with officials from Britain, France, Germany and Italy to get their signoff on the proposal.

French Foreign Minister Jean-Noël Barrot said Wednesday that the cease-fire would allow time for further negotiations and called on both parties “to accept it without delay.”

The Biden administration has also been communicating with Israel and indirectly with Hezbollah throughout the week. Blinken and senior Biden adviser Amos Hochstein met with Lebanese Prime Minister Najib Mikati on Wednesday, and Blinken is expected to meet Thursday with Ron Dermer, a senior adviser to Israeli Prime Minister Benjamin Netanyahu.

Danny Danon, the Israeli ambassador to the U.S., told reporters Wednesday that Israel supports a cease-fire.

“We welcome the initiatives from different negotiators, and I think they know exactly what we expect, and if you can achieve it with diplomacy, much better for Israel, much better for Lebanon,” he said.

Danon said Netanyahu would arrive in New York on Thursday and address the General Assembly on Friday morning. The Israeli leader is not, however, expected to meet with U.N. Secretary General António Guterres, Danon said.

As NBC News reported earlier this week, Guterres and Netanyahu have not spoken since the Oct. 7 attack, when Guterres’ call to Netanyahu to express solidarity went unanswered and unreturned — an indication of just how much the relationship between Israel and the U.N. has deteriorated.

Speaking Wednesday on MSNBC’s “Andrea Mitchell Reports,” Michael Herzog, the Israeli ambassador to the U.S., said Israel was “willing to give diplomacy a chance” but that “if diplomacy doesn’t work, I think we have to resort to other means to change the calculus and return our people to their homes.” 

Fears of ground invasion

Israel and Hezbollah have been exchanging a barrage of rockets across the Israel-Lebanon border for months now, and Israel says it has evacuated about 60,000 people from its northern region. In Lebanon, more than 100,000 have been displaced, according to the International Organization for Migration.

The violence worsened last week when pagers and walkie-talkies used by Hezbollah and surreptitiously packed with explosives were remotely detonated simultaneously, killing dozens of the group’s members as well as civilians and injuring thousands of others.

Hezbollah chief Hassan Nasrallah vowed revenge for the explosions, which Israel has not said it is responsible for, and the group responded Friday by bombing an air defense base and military barracks in northern Israel.

The explosions in Lebanon were followed by some of the most intense Israeli strikes in the country since Oct. 7, including a Friday strike against a senior Hezbollah commander in a suburb of Beirut in which dozens of people were killed.

Since Monday, Israel has dramatically expanded its aerial assault on Lebanon, issuing warnings for civilians to move away from Hezbollah positions. Almost 500 people were killed on Monday alone in the deadliest day of conflict between Israel and Lebanon since their 34-day war in 2006.

Thousands more people have left Lebanon for neighboring Syria, spending hours in traffic jams.

While the Israel Defense Forces said earlier that the campaign would be limited to aerial attacks, on Wednesday, the IDF chief of staff, Lt. Gen. Herzi Halevi, told his troops to prepare for a possible ground operation, which would be Israel’s first in Lebanon since 2006.

An Israeli ground invasion does not appear to be imminent, Pentagon spokesperson Sabrina Singh said Wednesday. She added that the U.S. military is not providing Israel with intelligence support for its current operations in Lebanon.

“When it comes to Lebanon, the U.S. military has no involvement in Israeli operations,” she said.