The United Nations Security Council on Monday adopted a resolution demanding an immediate cease-fire between Israel and Palestinian militant group Hamas, after the United States abstained from the vote — prompting Israel to cancel the visit of a high-level delegation to Washington.

Israeli Prime Minister Benjamin Netanyahu had warned before the vote that the delegation’s visit would be pulled, if Washington did not veto the motion. The U.S. abstention signals a widening divide between the White House and Israel’s current government, the most right-wing in its history, nearly six months into its war against Hamas in the Gaza Strip. Israel’s offensive into the Gaza enclave, which comes in response to the Oct. 7 Hamas terror attacks, has killed tens of thousands of people, according to Gaza’s Hamas-run Health Ministry.

“This is a clear retreat from the consistent position of the U.S. in the Security Council since the beginning of this war,” a statement from Netanyahu’s office said, adding that “this withdrawal hurts both the war effort and the effort to release the abductees.”

The U.S. denied that the abstention marked a shift in its policy. Some observers see it differently.

“It’s a breakthrough. An abstention from a UN Security Council permanent member is a yes vote, because it means they are not exercising their veto and basically agree with the text, even if they don’t want to say so,” Hussein Ibish, a senior resident scholar at the Arab Gulf States Institute in Washington, told CNBC.

“The U.S. declining to protect Israel from a resolution it passionately objects to by not providing a veto is an extraordinary thing.”

The first of its kind passed since the onset of the war, the resolution called for an immediate cessation of hostilities between Israel and Palestinian militant group Hamas for two weeks, breaking a five-month impasse during which the U.S. vetoed three U.N. calls for a halt in fighting. The motion also called for the immediate and unconditional release of all hostages held by Hamas in the Gaza Strip.

State Department spokesman Matthew Miller said Washington’s reasons to not approve the measure included its lack of condemnation for the Hamas terror attack, which led to roughly 1,200 deaths in Israel and took around 240 more people hostage.

But, Miller added, “the reason we didn’t veto it is because there were also things in that resolution that were consistent with our long term position, most importantly, that there should be a ceasefire and that there should be a release of hostages, which is what we understood also to be the government of Israel’s position. So it is a bit surprising and unfortunate that they are not going to apparently attend these meetings.”

The move follows condemnations of Netanyahu from a number of U.S. lawmakers — most notably, Senate majority leader Chuck Schumer, the highest-ranking Jewish member of Congress, who is known for steadfastly standing by Israel’s government over the years.

“In this case, the abstention is a very strong signal to Israel that the United States is losing patience,” Ibish said.

The cancelled Israeli delegation‘s visit to Washington was set to discuss Israel’s planned military operation in Rafah, the southernmost corner of Gaza, where more than a million displaced Palestinians are taking shelter and where Israel says the bulk of Hamas’ remaining fighters are located.

The Biden administration has warned against a Rafah operation, already frustrated by Israel’s hindering of aid deliveries into the besieged strip. At the start of the year, the U.N. warned that half a million Palestinians were facing famine.

For former Israeli foreign minister Shlomo Ben Avi, the rift between the two longtime allies is a grave threat to Israel’s security — and the blame lies with Netanyahu.

Asked by CNBC’s Dan Murphy if the U.S. and Israel are now at a turning point in the war, Ben Avi said:

“I think we definitely are. This is a crisis, [and] Americans are conveying the powerful message that they disagree on the way Israel is conducting the war, that they think this is the moment to move to a political process.”

He added, “The whole attitude of confronting Americans instead of serving with their interests, which are essentially Israel’s interests, is working against the nation’s security. Netanyahu has become a threat to Israel’s security by conducting war from the very first day. With him, political domestic consideration is more [important] than catering to the strategic interest of Israel.”

“America is fed up with this war,” the former minister said, “fed up particularly with Netanyahu who doesn’t behave as loyal ally, lacking gratitude for America’s political and military help in this war.”

CNBC has reached out to the Israeli Prime Minister’s office for comment.