The EU foreign policy chief has declared that “the free world needs a new leader”, as European leaders threw their support behind Ukraine’s president, Volodymyr Zelenskyy, after the stunning White House confrontation between him and Donald Trump.

Leaders from across Europe expressed their solidarity with the Ukrainian leader after the fractious exchange with JD Vance, the US vice-president, and Trump, who claimed he was not “ready for peace” and accused him of “gambling with world war three”.

Although in general the European leaders did not name the US president, their comments late on Friday laid bare the gaping rift between the US and its traditional allies in Europe over the war in Ukraine.

In a social media post Kaja Kallas, the EU high representative for foreign affairs and security policy, wrote: “Ukraine is Europe! We stand by Ukraine. We will step up our support to Ukraine so that they can continue to fight back the aggressor.

“Today, it became clear that the free world needs a new leader. It’s up to us, Europeans, to take this challenge.”

Addressing Zelenskyy directly, Ursula von der Leyen, the president of the EU Commission, wrote: “Your dignity honors the bravery of the Ukrainian people. Be strong, be brave, be fearless. You are never alone.”

She added: “We will continue working with you for a just and lasting peace.”

The British prime minister, Keir Starmer, who just a day before had visited Trump at the White House, called Zelenskyy to express his support, a No 10 spokesperson said.

Starmer – who failed in his effort to convince Trump to commit US support for a European-led peacekeeping force in Ukraine – told Zelenskyy that “he retains his unwavering support for Ukraine and is playing his part to find a path forward to a lasting peace, based on sovereignty and security for Ukraine”, the official said.

Two days after his own meeting with Trump in Washington the French president, Emmanuel Macron, responded indirectly to the US president’s baseless claims that Zelenskyy was responsible for the war, telling reporters: “Russia is the aggressor, and Ukraine is the aggressed people … These are simple things, but they’re good to remember at times like these.”

European leaders had already been shaken by Vance’s speech to the Munich security conference two weeks ago in which he lectured them about the state of their democracy.

Italy’s prime minister, Giorgia Meloni, called for an emergency meeting between the US, Europe and Ukraine.

“A summit without delay is needed between the United States, European states and their allies to talk frankly about how we intend to tackle today’s major challenges, starting with Ukraine, which together we have defended in recent years,” Meloni said in a statement.

Jonas Gahr Støre, Norway’s prime minister, described the episode as “serious and disheartening”.

“That Trump accuses Zelenskyy of gambling with world war three is deeply unreasonable and a statement I distance myself from,” he said.

The Spanish prime minister, Pedro Sánchez, said his country would stand by Ukraine after the row.

Sánchez, a staunch backer of Ukraine since Russia’s 2022 invasion who pledged €1bn of aid in a visit to Kyiv earlier this week, wrote on X: “Ukraine, Spain stands with you.”

Poland’s prime minister, Donald Tusk, was among the first to show his support for Zelenskyy and Ukraine on social media, telling them: “You are not alone.”

The outgoing German chancellor, Olaf Scholz, the Dutch prime minister, Dick Schoof, Luxembourg’s prime minister, Luc Frieden, and Portugal’s prime minister, Luís Montenegro, also professed their support for Ukraine, along with other leaders from Belgium, Croatia, the Czech Republic, Ireland, Finland, Latvia, Lithuania, Slovenia, and Sweden.

Canada’s prime minister, Justin Trudeau, said Ukraine’s fight against Russia is a defense of democracy.

“Russia illegally and unjustifiably invaded Ukraine. For three years now, Ukrainians have fought with courage and resilience. Their fight for democracy, freedom, and sovereignty is a fight that matters to us all,” he posted on X.

“Canada will continue to stand with Ukraine,” Trudeau added.

Some world leaders, however, sided with Trump.

Viktor Orbán, Hungary’s prime minister, wrote on X: “Strong men make peace, weak men make war.

“Today President @realDonaldTrump stood bravely for peace. Even if it was difficult for many to digest. Thank you, Mr. President!”

Orbán, an outspoken critic of western aid to Ukraine, has been at odds with other Nato countries over Orbán’s continued cultivation of close ties to Russia.