Transcript for Trump responds to Trudeau's tariff threat

And the summit of course with North Korea comes on the heels of a tense G-7 economic summit in Quebec Canada. For president from clash with the prime minister there and other US allies. He faced off with the other top industrial nations over what he sees as unfair trade practices that it's this photo that many were talking about. A White House advisor claiming the Canadian leader is a back stab or in this morning the president. Is back on Twitter lashing out yet again. ABC's are what science is following the developments from DC good morning. Good morning pandas and Diana while president trump is in Singapore are ready to make nice with one of America's. Fiercest enemy is but when it comes to one of the country's closest ally is the president is engaged in an epic clash. President shrub and his top aides are on the attack against Canadian prime minister Justin Trudeau here's the thing me. From Singapore the president tweeted sorry we cannot let our friends or enemies take advantage of us on trade any more we must put the American worker first. This comes after the president ruffled feathers at the G-7 summit. Not backing down from stiff tariffs on aluminum and steel imports from Canada and other US allies. The president calling it a matter of national security. The national security pretense. It's Syria and frankly insulting T Canadians. V closest and strongest ally the United States. Has for dope promised to fight back by slapping tariffs on American goods. Polite we're reasonable but we also will not be pushed around. That move infuriated the president who lashed out in an angry tweet calling Trudeau very dis honest and two week. And then a stunning decision the president refused to sign a traditional statement of solidarity with the G-7 partners. The White House moves into full attack mode. There's a a special place in hell for any foreign leader. That engages in bad faith diplomacy would president Donald. The clash over tariffs could lead to higher prices on goods like cars. And even cans of beer the beer institute said the industry could face a 348. Million dollar hit. Each year said Diana Candace says Beers he had over the weekend and their prices might be going up. Bombers.

This transcript has been automatically generated and may not be 100% accurate.