World leaders reacted with shock to the wounding of Donald Trump in an assassination attempt against the former US president at a campaign rally in Butler, Pennsylvania.

Presidents and prime ministers from all over the world spoke out against political violence and expressed their support for those affected by the shooting on Saturday, which killed one bystander and left two other spectators critically wounded.

The European Union's foreign policy chief, Josep Borrell, condemned the attack.

"Once again, we are witnessing unacceptable acts of violence against political representatives," the bloc's top diplomat said.

British Prime Minister Keir Starmer said Sunday he was "appalled by the shocking scenes" at the rally.

"Political violence in any form has no place in our societies," the premier said.

Referring to "these dark hours", Hungary's nationalist leader Viktor Orban offered his "thoughts and prayers" to Trump.

Italian Prime Minister Giorgia Meloni said she was "following with apprehension" updates from Pennsylvania and wished Trump a speedy recovery.

The far-right leader expressed her hope that "in the following months of the electoral campaign, dialogue and responsibility can prevail over hate and violence."

Olaf Scholz, the German chancellor, called the attack "despicable" and added: "Such acts of violence threaten democracy."

Ukraine's President Volodymyr Zelensky said he was "appalled to learn about the shooting" and wished Trump a "speedy recovery".

"Such violence has no justification and no place anywhere in the world. Never should violence prevail," he said.

Moscow called on the US to "take stock" of its "policies of incitement to hatred," while using the assassination attempt on former president Donald Trump to denounce support for Ukraine.

Addressing "those who vote in the United States to supply arms" to Kyiv, the Russian foreign ministry spokesperson Maria Zakharova denounced support for Kyiv, which she said stoked "attacks against the Russian president."

She added that "perhaps it would be better to use this money to fund the American police and other services that are supposed to ensure law and order in the United States?"

Argentina's President Javier Milei baselessly blamed the "international left" after the assassination attempt.

"In panic of losing at the polls, they resort to terrorism to impose their backward and authoritarian agenda," said the populist president.

Brazil's President Luiz Inácio Lula da Silva said the shooting "must be strongly condemned by all defenders of democracy and political dialogue."

Costa Rica's government condemned the attack and said it was following updates on "this unacceptable act".

"As a leader in democracy and peace, we reject all forms of violence," the presidency said.

Chilean President Gabriel Boric expressed his "unqualified condemnation" of the shooting.

"Violence is a threat to democracies and weakens our life together. We must all reject it," said Boric.

In Bolivia, President Luis Arce said "despite our deep ideological and political differences, violence, wherever it comes from, must always be rejected by everyone."

Indian Prime Minister Narendra Modi said he was "deeply concerned by the attack on my friend."

"Violence has no place in politics and democracies," Modi said.

Japanese Prime Minister Fumio Kishida also spoke out against political attacks, saying "we must stand firm against any form of violence that challenges democracy."

Taiwan's President Lai Ching-te offered his "sincere condolences" to the shooting victims. "Political violence of any form is never acceptable in our democracies," he said.

Chinese leader Xi Jinping "expressed his condolences to former President Trump," per a statement by China's foreign ministry.

Philippine President Ferdinand Marcos said it was "with great relief that we receive the news that former President Donald Trump is fine and well after the attempt to assassinate him".

"Together with all democracy loving peoples around the world, we condemn all forms of political violence. The voice of the people must always remain supreme," Marcos said.

Australian Prime Minister Anthony Albanese said he was "shocked by the terrible scenes" at the Trump campaign event, expressing his relief that the former US president was safe.

"This was an inexcusable attack on the democratic values that Australians and Americans share and the freedom that we treasure," Albanese said.

New Zealand's Prime Minister Chris Luxon echoed these views, writing "no country should encounter such political violence."

Israel's Prime Minister Benjamin Netanyahu said he and his wife Sara "were shocked by the apparent attack on President Trump".

"We pray for his safety and speedy recovery," Netanyahu said.