"It's never been done, It's never been tested".
Macron has said how unhappy he is with U.S.
The two leaders are set to meet on Tuesday morning at the Capella Hotel on the Singaporean resort island of Sentosa.
Trump added: "Very dishonest & weak".
He also defended the wisdom of his controversial tariffs, saying that the USA would win a trade war against its allies because "they do so much more business with us than we do with them".
He did not explain what kind of trade deal he was looking for.
Soon after the joint statement was announced, the U.S. president tweeted defiantly about not allowing "other countries to impose massive tariffs and trade barriers on its on farmers, workers and companies".
I think it would be good the United States.
Speaking to reporters at the annual G-7 meeting, the president said that totally eliminating trade barriers between the nations would be "the ultimate thing" and "that's the way it should be".
"Canadians, we're polite, we're reasonable, but we also will not be pushed around".
'There will not be a sunset clause. we will not, can not sign a trade deal that expires automatically every five years, ' he told a news conference at the end of a Group of Seven summit in Quebec.
In a separate post, Trump said the host country Canada "charges the us a 270% tariff on Dairy Products!"
"The other leaders have been calling this G6 + 1 because Trump has been so isolated ever since this began, and that's because he launched an outright attack - that's in the view of the other members - on the global trading system by raising tariffs on steel and aluminum".
"We're going to deal with the unfair trade practices", Trump told reporters outside the White House before leaving for the summit. "And they understand it's going to happen". Trump said the final outcome would lead either to a better agreement on NAFTA or separate trade deals with both Canada and Mexico. They were looking at what appeared to be a draft document marked up with highlighter.
Meanwhile, Canadian premier Justin Trudeau has warned that Trump's tariffs "are hurting his own citizens. I have been Russia's worst nightmare", Trump said.
Russia was ousted from the elite group in 2014 as punishment for Vladimir Putin's annexation of Crimea, and its support for pro-Russian separatists in Ukraine.
That leaves Trump diametrically opposed with Canada, which says renegotiating the deal every five years would create perpetual uncertainty and harm long-term investment.