Group of Seven leaders, including US President Donald Trump, are preparing to hold talks later in Canada, tackling issues including whether they can find common ground on an escalating conflict between Iran and Israel.
The three-day gathering in the mountain town of Kananaskis marks the return to the international diplomatic calendar for Mr Trump, who has stunned allies by defying norms and slapping sweeping tariffs on friend and foe alike.
Canadian Prime Minister Mark Carney had designed an agenda aimed at minimising disagreements within the club of wealthy industrial democracies, Britain, Canada, France, Germany, Italy, Japan and the United States.
However, Israel shocked the world two days before the summit with a surprise, massive military campaign against Iran.
Canada is now sounding out countries about making a joint call on Israel and Iran, diplomats said.
The statement could call for de-escalation or could simply back Israel, saying that it has a "right to defend itself" due to Iran's contested nuclear work.
European Commission President Ursula von der Leyen told reporters that she spoke with Israeli Prime Minister Benjamin Netanyahu before the summit and agreed that Iran was to blame.
"Of course I think a negotiated solution is, in the long term, the best solution," she said, stopping short of calling for an immediate ceasefire.
President Trump has praised Israel's strikes, noting it used US weapons, even though Mr Netanyahu defied his public calls to hold off as the United States sought a negotiated solution.
Unusually, Japan, which historically has maintained cordial ties with Iran, made a forceful break with allies in the United States and Europe when it denounced Israel's strikes as "deeply regrettable".
European powers have all steered clear of criticising Israel on the Iran strikes, despite separate concerns about the humanitarian situation in besieged Gaza.
French President Emmanuel Macron has called for restraint and urged Iran to re-enter talks with the United States, while also blaming Tehran for escalating tensions over its nuclear programme.
Mr Trump is visiting Canada despite his mockery of the United States' northern neighbour, which he has said would be better off as the 51st state.
Tensions have eased since Mr Carney, a former central banker, took over in March from Justin Trudeau, an erstwhile star on the global stage whom Mr Trump made no secret of disliking.
When President Trump last visited Canada for a G7 summit in 2018, he bolted out early and tweeted from Air Force One insults about Mr Trudeau, disassociating the United States from the final statement.
However, deep tensions remain. Mr Trump, seeking a radical transformation of a global economic order centered on free trade, has vowed to slap sweeping tariffs on US friends and foes alike on 9 July, a deadline he postponed once.
Ms von der Leyen, who spoke to Mr Trump by telephone on Saturday, voiced hope that the Europeans can reach a solution and offered veiled criticism of the US approach.
"Let us keep trade between us fair, predictable and open. All of us need to avoid protectionism," she said.
Ms von der Leyen also called for the G7 to link the crises in Iran and Ukraine, which has been hit by drones sold to Russia by Iran's cleric-run state.
"The same type of Iranian-designed and -made drones and ballistic missiles are indiscriminately hitting cities in Ukraine and in Israel. As such, these threats need to be addressed together," she said.
Ukrainian President Volodymyr Zelensky is among the invited guests and hopes to speak to Mr Trump, who publicly derided him when they met at the White House on 28 February.
Mr Trump had hoped to force Ukraine into a quick deal with Russia, but he has grown frustrated after President Vladimir Putin refused US-led appeals for at least a temporary truce.
He spoke by telephone with President Putin on Saturday, both about the Israel-Iran conflict and Ukraine.
Mr Macron, however, cast doubt on Mr Putin serving as a Middle East mediator.
The French president headed to Kananaskis after stopping in Greenland, where he denounced Trump's threats to seize the Danish autonomous territory.
"That's not what allies do," he said.
Mr Trump for his part arrived at the summit after attending a military parade in Washington that coincided with his birthday, prompting nationwide protests over steps seen as increasingly authoritarian.
