BRUSSELS, Belgium - British Prime Minister Theresa May condemned a blunt speech this week by Secretary of State John Kerry on the state of the Israeli-Palestinian conflict, an unusual move that boosted Britain's relations with the incoming Trump administration at the expense of President Obama.

The rare diplomatic spat between Britain and the United States, which was met with surprise by the State Department, highlighted the fast-collapsing influence of the lame-duck White House. It also pointed to a vast reordering of international affairs expected after Trump takes office in three weeks, as U.S. allies position themselves to curry favor in the new order.

The transatlantic split was particularly unexpected given that May's government acted as a key broker between U.S. and Palestinian interests ahead of a U.N. Security Council vote last week to declare Israeli settlement construction "illegal." British diplomats worked as go-betweens in shaping the measure to ensure that the language was acceptable to the United States, Britain's Guardian and Israel's Haaretz newspapers reported this week.

Kerry on Wednesday offered a harsh assessment of the government of Israeli Prime Minister Benjamin Netanyahu, saying that "his current coalition is the most right wing in Israeli history, with an agenda driven by its most extreme elements." He criticized persistent Israel settlement expansion in the West Bank as a threat to the "two-state solution" under which Israel and a new Palestinian state would coexist side by side.

May's office retorted that "we do not believe that it is appropriate to attack the composition of the democratically elected government of an ally." It said in an emailed statement late Thursday that "we are also clear that the settlements are far from the only problem in this conflict. In particular, the people of Israel deserve to live free from the threat of terrorism, with which they have had to cope for too long."

The move was an olive branch both to Netanyahu and to President-elect Donald Trump, who railed against the Obama administration's decision to abstain from a U.N. Security Council resolution condemning the settlements and who has urged Israel to "stay strong" until he assumes office Jan. 20. Trump has expressed near-unconditional support for actions by the Israeli government, breaking with long-standing U.S. policy that has sought a middle ground between the two sides.

Kerry's speech and the U.S. abstention in the Security Council vote were received warmly by Germany and France, among other European nations, which led to a stunned reaction in Washington to the message from May's office.

"We are surprised by the U.K. Prime Minister's office statement given that Secretary Kerry's remarks - which covered the full range of threats to a two-state solution, including terrorism, violence, incitement and settlements - were in line with the U.K.'s own long-standing policy and its vote at the United Nations last week," the State Department said in a statement.

British leaders have publicly embraced Trump since his victory last month, despite his urging that Nigel Farage, a lead campaigner for Britain's exit from the European Union and a thorn in the side of the British government, be named British ambassador to Washington.

Britain, which is preparing to negotiate the terms of a messy exit from the EU, is hoping that a strong economic relationship with the United States will help smooth out the disruptions.

During his presidential campaign, Trump praised Britain's vote to leave the European Union and took to calling himself "Mr. Brexit."

This week, Britain's ambassador in Washington, Kim Darroch, expressed hope that Trump and May would build "on the legacy of previous leaders such as President Reagan and Prime Minister Margaret Thatcher."

Kerry's hour-long speech Wednesday was unusual in its breadth and frankness, coming from a man who devoted much of his energy as the top U.S. diplomat toward Israeli-Palestinian negotiations that were ultimately abandoned.

Kerry said Wednesday that Israeli settlement activity, which has accelerated in recent years, was extending far into the West Bank, "in the middle of what, by any reasonable definition, would be the future Palestinian state."

The Obama administration intended the abstention on the U.N. resolution as a warning sign to the Netanyahu government that international support would not be unconditional, as settlement populations swell on territory extending beyond the pre-1967 armistice lines that defined Israel's boundaries.