Israeli Prime Minister Benjamin Netanyahu and the UK's Keir Starmer have been among the first world leaders to congratulate Donald Trump on winning the US presidential election.
The election of a new president is not just a big deal for the US - a new leader in the White House can transform the country's foreign policy and its position towards its friends and foes internationally.
Here is how some of the world's leaders have reacted so far.
In his statement, Netanyahu - who has had a difficult relationship with President Joe Biden - spoke of "history’s greatest comeback", adding that Trump's return to office offered a "new beginning for America, a powerful recommitment to the great alliance between Israel and America".
Senior Hamas official Sami Abu Zuhri said that Trump would be tested on his statements that he can stop the war within hours as US president.
"We urge Trump to learn from Biden's mistakes," he told Reuters news agency.
UK Prime Minister Sir Keir Starmer said: "I look forward to working with Trump in the years ahead."
He added: “From growth and security to innovation and tech, I know that the UK-US special relationship will continue to prosper on both sides of the Atlantic for years to come."
Hungarian Prime Minister Viktor Orban - a close Trump ally - said his election was "a much-needed victory for the world".
"The biggest comeback in US political history!" he wrote in a post on X.
Orban had openly endorsed Mr Trump's re-election bid, after being the first and only EU leader to back him in 2016.
French President Emmanuel Macron also congratulated Trump, saying he was ready to work together with him just as before, "with respect and ambition. For more peace and prosperity".
Macron also said that he had held talks with German Chancellor Olaf Scholz, over working to defend Europe's interests and values while co-operating with the US.
German Chancellor Olaf Scholz congratulated Trump, adding that "Germany and the US have for a long time successfully worked together to promote prosperity and freedom on both sides of the Atlantic".
Nato Secretary General Mark Rutte said Trump's leadership "will again be key to keeping our alliance strong. I look forward to working with him again to advance peace through strength through Nato".
Donald Trump has been critical of the Nato alliance, accusing its European allies of not paying enough for security.
Ukrainian President Volodymyr Zelensky said on X: "I appreciate President Trump’s commitment to the 'peace through strength' approach in global affairs. This is exactly the principle that can practically bring just peace in Ukraine closer."
Trump promised to push Zelensky to cut a deal with Russian President Vladimir Putin, one that may involve a loss of territory. Ukraine fears he will reduce US military and financial support.
Italian Prime Minister Giorgia Meloni congratulated Trump in a post on X, saying Italy and the US were "linked by an unshakable alliance, common values and a historic friendship. It is a strategic bond, which I am sure we will now strengthen even further."
Spanish Prime Minister Pedro Sanchez also congratulated Trump on X: "We will work on our strategic bilateral relations and on a strong transatlantic partnership."
Irish Prime Minister Simon Harris said Ireland "will work to deepen and strengthen the historic and unbreakable bonds between our people and our nations in the years ahead".
In her congratulatory message to Trump, European Commission President Ursula von der Leyen said the EU and the US were "more than just allies".
Kremlin spokesperson Dmitry Peskov said he was "not aware of the president's plans to congratulate Trump on the election", since the US was an "unfriendly country".
He added that Russia would judge Trump on his actions: "We will draw conclusions based on concrete steps and concrete words."
Indian Prime Minister Narendra Modi congratulated Trump, describing him as a friend on X: "As you build on the successes of your previous term, I look forward to renewing our collaboration to further strengthen the India-US Comprehensive Global and Strategic Partnership.
"Together, let's work for the betterment of our people and to promote global peace, stability and prosperity."
Turkey's President Tayyip Erdogan also called Trump a friend, adding that he believed "more efforts will be given for a fairer world in this new era that began with the election by American people".
Australian Prime Minister Anthony Alabanese said the US "has long played a leadership role in the stability and security of the Indo-Pacific. Australia will strive to strengthen the co-operation between our two nations in the region."
During a routine news briefing, Chinese ministry of foreign affairs spokesperson Mao Ning said "the US presidential election is their domestic affairs. We respect the American people’s choice".
Trump threatened to impose massive trade tariffs on Chinese goods coming into the US, and he may push Europe to decouple more from China’s economy.
Speaking to reporters, Taiwan's National Security Bureau Director-General Tsai Ming-yen said: "On relations across the Taiwan Strait, we believe that the US will continue its current approach of constraining China and being friendly to Taiwan."
Philippine President Ferdinand Marcos Jnr said that with Trump's election, "the American people triumphed, and I congratulate them for their victory in an exercise which showed the world the strength of American values."