Donald Trump declared that he was on a "mission of peace" before leaving the G7 summit early to meet Kim Jong Un in Singapore.

He told reporters he would "know within a minute" whether Mr Kim was serious about giving up his nuclear weapons, adding that he would not prolong talks if he sensed otherwise.

The US leader boarded a plane from Quebec on Saturday ahead of the highly anticipated meeting with the North Korean leader on Tuesday, leaving G7 leaders early and missing environmental talks.

Image: President Trump has left for Singapore

Speaking to reporters before his flight, President Trump said he suggested to his G7 colleagues that all trade barriers between their countries - including tariffs and subsidies - be eliminated.

"You go tariff-free, you go barrier-free, you go subsidy free," he said. "I did suggest it and people I guess were going to go back to the drawing board."


Trump threatens to stop trading

The president said the group was starting to be more committed to "fairer trade" with the United States

He warned them against retaliation after the US imposed tariffs on steel and aluminium from Europe, Mexico and Canada - saying they would be "making a mistake".

"The United States has been taken advantage of for decades and decades," he said.

Mr Trump said he did not blame the G7 for trade deals but warned "those days are over".

Trump boards plane ahead of Kim summit

The president said the US was prepared to stop trading with some countries if things did not change - citing India as one country that puts tariffs as high as 100% on American goods.

Later, Mr Macron said a soon-to-be-released joint statement from all seven countries would provide a sign that attempts to "stabilise things" on trade were working.

The summit was dubbed "the G6 plus one" due to the billionaire tycoon's isolation over trade and his decision to pull the US out of the Iran nuclear deal.

One sign of tension - or not - was seen in an exceptionally firm handshake between Mr Macron and the US leader - with a picture showing how the gesture left its mark on Mr Trump.

:: Photos hint at tension behind scenes at G7

Image: Mr Macron left his mark on Mr Trump's hand after a firm handshake

However, Mr Trump said the summit had been "really tremendously successful" and that the leaders were "bound together by shared values and beliefs".

The American president said his relationship with his counterparts was a "10", citing Canada's Justin Trudeau, Germany's Angela Merkel and France's Emmanuel Macron - but there was no namecheck for Theresa May.

Trump doesn't name May among top allies

He also called for Russia to return to the group of world leaders once more, saying it would be "a positive thing" to move back to a G8.

"I think the G8 would be better. I think having Russia back in would be a positive thing," he said. "We're looking for peace in the world. We're not looking to play games."

G7 leaders gather for family photo

The call came despite European members of the G7 earlier rejecting Mr Trump's plea to reinstate Russia.

As he prepared to leave Canada for Singapore, Mr Trump remained optimistic about his meeting with the North Korean leader.

How will fiery Trump and Kim get along?

He said Mr Kim "wants to do something great for his people" and called the meeting a "one-time shot" for peace and denuclearisation.

President Trump said he thought the North Korean leader was "going to do something positive", adding: "I think it's going to work out well."