John Kerry, the outgoing US secretary of state, has issued a desperate final warning that settlement-building policies being carried out by Israel's Government are destroying hopes for peace, just hours after Donald Trump promised to reverse current United States policy toward Israel.
With three weeks left in his post, Kerry used one of his last major speeches to say the "most extreme elements" of Israel's right-wing were shaping the country's future and strangling the prospect of a two-state solution.
"The settler agenda is defining the future of Israel and their stated purpose is clear: they believe in one state," Kerry said. "We cannot, in good conscience, do nothing and say nothing, when we see the hope of peace slipping away."
But before he even began his 71-minute speech, he was contradicted by a series of tweets from President-elect Trump, who accused the Obama Administration of showing "total disdain and disrespect" for Israel.
"Stay strong Israel, January 20th is fast approaching!" he added, referring to the day he will replace Barack Obama as President.
Kerry's speech also drew a furious reaction from Benjamin Netanyahu, the Israeli Prime Minister, who said the US diplomat focused "obsessively" on Jewish settlements and "barely touched" on Palestinian opposition to a Jewish state in any form.
The unprecedented public clash pitting the outgoing American Administration against the incoming Administration and the Israeli Government came days after the US allowed a resolution criticising Israeli settlements to pass the United Nations Security Council.
And it came as Trump accused Obama of derailing a smooth transition with "inflammatory" statements and "roadblocks" in an unprecedented personal condemnation of a soon-to-be predecessor.
Ever since the election, Trump and Obama have tried to bury political differences in favour of a united public front that would smooth the transfer of power.
But tensions have come to the fore in recent days, with Obama recently suggesting that he could have won a third term in office if he had been able to run.
Israel launched an angry diplomatic and rhetorical campaign against the White House and the 14 countries, including New Zealand, that voted for the UN resolution.
Kerry spent months trying to negotiate a peace deal between Israelis and Palestinians in 2013 and 2014 but has since become an increasingly vocal critic of Israeli settlement building in east Jerusalem and the occupied West Bank. "No one thinking seriously about peace can ignore the reality of what the settlements pose to that peace," he said.
Trump has signalled he does not share the Obama Administration's concerns and intends to staunchly support Netanyahu's pro-settler Government.
His nominee for US ambassador to Israel is a right-wing lawyer who opposes the creation of an independent Palestinian state and has raised money for Jewish settlements.
Kerry acknowledged "that a speech alone won't produce peace" but said he hoped his words would serve as a warning that time was running out for a two-state solution.
He also suggested a series of principles for a future peace deal, including dividing Jerusalem so it could serve as a capital for both Israel and Palestine, compensating the descendants of Palestinian refugees who fled their homes in 1948, and ensuring Israel's security.
He said Palestinians need to do more to end incitements to violence against Israelis. But he devoted more time to criticising Israeli policies and the rhetoric of Israeli government ministers.
"Like the Security Council resolution that Secretary Kerry advanced in the UN, his speech tonight was skewed against Israel," Netanyahu said.
"For over an hour, Kerry obsessively dealt with settlements and barely touched upon the root of the conflict - Palestinian opposition to a Jewish state in any boundaries."
While anxious about what further moves the Obama Administration may make before leaving office, the Israeli prime minister appears to have taken heart from Trump's words of encouragement. "President-elect Trump, thank you for your warm friendship and your clear-cut support for Israel!" he tweeted in response to one of the President-elect's own tweets, tagging Trump and his daughter, Ivanka.Telegraph Group Ltd