US, Israel at standoff over Lebanon cease-fire proposal. What happened?

A 21-day cease-fire proposal aimed at pausing the conflict in Lebanon has become the latest flashpoint in the strained relationship between the Biden administration and Israel after the country's prime minister, Benjamin Netanyahu, roundly rejected the terms of the proposal on Thursday.

As the prime minister flew to New York ahead of his Friday address to the annual high-level gathering of the United Nations, his office issued a statement saying he "did not even respond" to the proposal put forth by the U.S. and France, and that he had instructed the Israeli military to continue fighting against the Lebanese militant group Hezbollah "with full force."

Netanyahu's rejection came just hours after White House officials lauded a joint statement issued by the U.S., the European Union and six other countries endorsing the plan for a 21-day truce, a step heralded as an "important breakthrough."

Washington said Israel had been consulted before the joint statement was released, but struggled to explain the apparent disconnect.

"We wouldn't have worked on that statement the way we did. We wouldn't have issued it when and how we did if it wasn't supported by the conversations that we were having with top Israeli officials yesterday," National Security Council spokesperson John Kirby said on Thursday.

But behind the scenes, several U.S. officials familiar with the negotiations told ABC News they have consistently seen getting Israel to sign off on a truce as an uphill battle.

Israel views a pause as beneficial to Hezbollah because it could allow it to regroup and strike back at Israel following attacks on the militant group's communication system last week widely attributed to Israel, according to the officials.

They say that the Israeli government also views a truce of any length as running counter to its main aim of allowing people displaced from areas near its northern border to return to their homes as soon as possible.

Israel's permanent representative to the U.N., Danny Danon, told reporters on Wednesday that Israel would prefer to end its conflict with Hezbollah via diplomacy, but that "if it fails to return our residents to the homes, then we will use all means at our disposal."

"We are very honest about it," Danon said, adding that he believed the mediators "know exactly what we want."

The latest disconnect between the U.S. and Israel appears poised to add additional strain to what was already expected to be a contentious address to the U.N. by Netanyahu on Friday.

U.N. Secretary-General António Guterres warned the body's Security Council on Wednesday that "hell is breaking loose in Lebanon."

The U.N. Refugee Agency added on Thursday that in just 72 hours, more than 90,000 people had been displaced in Lebanon.

Shortly after Hamas' Oct. 7 attack on Israel, Hezbollah -- a U.S.-designated terrorist organization -- began firing rockets across the Lebanese border with Israel. The low-level conflict continued for nearly a year, repeatedly threatening to escalate before Israel stepped up its military campaign earlier this month.