US President Donald Trump is confronting the consequences of his preference to go it alone, with low expectations that the leaders of the richest democracies can make substantive progress on an array of issues at the G7 summit in France.

The meeting of the G7, Britain, Canada, France, Germany, Italy, Japan and the US, in the beach resort town of Biarritz comes at one of the most unpredictable moments in Mr Trump’s presidency, when his public comments and decision-making increasingly have seemed erratic and acerbic.

Mr Trump, who arrived Saturday, and his counterparts are facing mounting anxiety over the state of the world economy and new tension on trade, Iran and Russia .

Mr Trump, growing more isolated in Washington, might find a tepid reception at the summit as calls increase for co-operation and a collective response to address the financial downturn.

White House aides claimed he engineered a late change to the summit agenda, requesting a working session on economic issues.

The economic warning signs, along with Chinese’s aggressive use of tariffs on US goods, are raising the pressure on Mr Trump and his re-election effort.

He intends to push allies at the summit to act to promote growth.

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Donald Trump, second left, and First Lady Melania Trump, left, are greeted by Emmanuel Macron and his wife Brigitte (Sean Kilpatrick/The Canadian Press/AP)

Only hours before his arrival in Biarritz, Mr Trump had threatened anew to place tariffs on French wine imports to the US in a spat over France’s digital services tax – the European Union promised to retaliate.

That was the backdrop for a late addition to his summit schedule, a two-hour lunch with French President Emmanuel Macron outside the opulent Hotel du Palais.

The summit host said the two men were discussing “a lot of crisis” around the world, including Libya, Iran and Russia, as well as trade policy and climate change.

But he also echoed Mr Trump’s calls for Europe to do more to address the global slowdown, including by cutting taxes.

“When I look at Europe, especially, we need some new tools to relaunch our economy,” Mr Macron said.

Mr Trump insisted that despite tensions, he and Mr Macron “actually have a lot in common” and a “special relationship”.

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Canadian Prime Minister Justin Trudeau, left, is greeted by Emmanuel Macron and his wife (Sean Kilpatrick/The Canadian Press/AP)

In a later tweet, he said: “Big weekend with other world leaders!”

Mr Macron outlined details of a French plan to ease tensions with Iran by allowing Iran to export oil for a limited amount of time, said a French diplomat.

In exchange, Iran would need to fully put in place the 2015 nuclear deal, reduce tensions in the Persian Gulf and open talks.

The plan was met with a sceptical reception by Mr Trump, and the White House paid only a cursory mention of the Gulf in its official report of the lunch meeting.

Mr Trump planned to press leaders about what can be done to spur growth in the US and abroad, as well as to open European, Japanese and Canadian markets to American manufacturers and producers.

He has imposed or threatened to impose tariffs on all three markets in his pursuit of free, fair and reciprocal trade.

The annual G7 summit has historically been used to highlight common ground among the world’s leading democracies.

But in a bid to work around Mr Trump’s impulsiveness, Mr Macron has eschewed plans for a formal joint statement from this gathering.

Many of the summit proceedings will take place behind closed doors, in intimate settings designed for the leaders to develop personal relationships with one another.

On Saturday night they dined at the Biarritz lighthouse, with commanding views of the Bay of Biscay.