Options to fund Kyiv's war needs against invasion by Russia could feature prominently at the talks in Canada's Niagara region on the US border.

The diplomats are meeting after US President Donald Trump slapped sanctions on Moscow's two largest oil companies in October, slamming Russian President Vladimir Putin over his refusal to end the conflict.

Trump has also pushed other European countries to stop buying oil that he says funds Moscow's war machine.

Ukraine is enduring devastating Russian attacks on its energy infrastructure, but Canadian Foreign Minister Anita Anand stopped short of promising concrete outcomes to aid Kyiv at the Niagara talks.

She told AFP a priority for the meeting was broadening discussion beyond the Group of Seven, which includes Britain, Canada, France, Germany, Italy, Japan and the United States.

"For Canada, it is important to foster a multilateral conversation, especially now, in such a volatile and complicated environment," Anand said.

Representatives from Saudi Arabia, India, Brazil, Australia, South Africa, Mexico and South Korea will also be at the meeting held a short drive from the iconic Niagara Falls.

US Secretary of State Marco Rubio will hold bilateral talks with Anand on Wednesday, the second and final day of the G7 meeting.

Anand said she did not expect to press the issue of Trump's trade war, which has forced Canadian job losses and squeezed economic growth.

"We will have a meeting and have many topics to discuss concerning global affairs," Anand told AFP.

"The trade issue is being dealt with by other ministers."

Trump abruptly ended trade talks with Canada last month -- just after an apparently cordial White House meeting with Prime Minister Mark Carney.

The president has voiced fury over an ad, produced by Ontario's provincial government, which quoted former US president Ronald Reagan on the harm caused by tariffs.

- Sudan, Critical minerals -

Italy's foreign ministry said there will also be discussions on Sudan, gripped by a war since April 2023 that has created one of the world's worst humanitarian crises.

Delivering aid to the war-ravaged African country will be a focus of the talks, which come hours after UN humanitarian coordinator Tom Fletcher met with Sudan's army chief Abdel Fattah al-Burhan on getting life-saving supplies to civilians.

The G7's top diplomats are meeting two weeks after the grouping's energy secretaries agreed on steps to counter China's dominance of critical mineral supply chains, a growing area of concern for the world's industrialized democracies.

Beijing has established commanding market control over the refining and processing of various minerals -- especially the rare earth materials needed for the magnets that power sophisticated technologies.

The G7 announced an initial series of joint projects last month to ramp up refining capacity that excludes China.

While the United States was not party to any of those initial deals, the Trump administration has signaled alignment with its G7 partners.

A State Department official told reporters ahead of the Niagara meet that critical mineral supply chains would be "a major point of focus."

"There's a growing global consensus amongst a lot of our partners and allies that economic security is national security," the official said.