Leaders of the G7 group are gathering in Canada for what could be one its most acrimonious summits in years.

On the eve of the meeting, the French and Canadian leaders clashed with US President Donald Trump on the summit's key agenda - trade tariffs.

Mr Trump, expected to be the last to arrive and first to leave, has imposed steel and aluminium tariffs that have sparked reprisals from trade partners.

But the nations could also clash on the Iran nuclear deal and climate change.

The G7 summit, which groups Canada, the US, the UK, France, Italy, Japan and Germany, begins on Friday in the town of La Malbaie in Quebec.

The leaders of the nations, which represent more than 60% of global net worth, meet annually. Economics tops the agenda, although the meetings now always branch off to cover major global issues.

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