Trump's tweet came a day after he ignited global condemnation by imposing tariffs on steel and aluminum imports from Canada and two other key United States allies - the European Union and Mexico.
Finance leaders of the closest US allies vented anger over the Trump administration's metal import tariffs but ended a three-day meeting in Canada on Saturday with no solutions, setting the stage for a heated fight at a G7 summit next week in Quebec.
Trudeau, in his own statement, called the idea that Canada, "America's most steadfast ally", be considered a national security threat to the United States "simply ridiculous" and "inconceivable".
"Our steel and aluminium industries are hugely important to the United Kingdom, but they also contribute to U.S. industry including in defence projects which bolster USA national security." she said.
May says Britain and the European Union "will continue to work together to protect and safeguard our workers and industries".
He was speaking a day after International Trade Secretary Liam Fox refused to rule out a trade war after the US imposed tariffs of 25 percent on steel and 10 percent on aluminum imported from the EU, Canada and Mexico. "So, we will immediately introduce a settlement dispute with the WTO and will announce counter-balancing measures in the coming hours", Juncker said in a speech in Brussels. "It is pure protectionism", she said.
U.S. Commerce Secretary Wilbur Ross is expected to meet Chinese Vice Premier Liu He on Sunday, a U.S. government official said, as officials from the world's two biggest economies try to calm an escalating trade spat that has rattled financial markets.
"But we see no sign of that in this action today by the USA administration", Trudeau said.
Summit with Trump, North Korean leader Kim Jong Un back on
But Trump said he didn't like that Kim Jong Un had met Thursday in Pyongyang with Russian Foreign Minister Sergey Lavrov. Senate Majority Leader Mitch McConnell (R-Ky.) in Louisville warned Trump to be dispassionate about North Korea.
France will give citizenship to "spider-man" who saved the baby
The report went on to say Mr Gassama had moved to France only months earlier in search of somewhere to build his life. The father of the child was detained overnight for alleged parental neglect, and is to appear in court in September.
Kyrie Irving underwent nasal surgery prior to Game 7
Before picking either side in the 2018 NBA Playoffs, you need to read what SportsLine senior analyst Larry Hartstein has to say. And while the chase-down block might be James' signature version, this more traditional swat was no less remarkable.
Janzen says the steel and aluminum tariffs are a unique result of Trump policies whereas softwood lumber has been an irritant for several administrations of both political parties.
European Union trade commissioner Cecilia Malmstrom in Brussels on Friday.
He says NAFTA has been "a very lousy deal" for the USA and says, "they're our allies but they take advantage of us economically".
Former British trade minister Francis Maude has condemned the United States' decision to impose tariffs on steel and aluminum imports as "stupid" and counterproductive. A previous steel dispute with the United States in 2002 took one and a half years with a final decision that fell in favour of the EU.
Malmstrom said the Trump measures "will cause a lot of damage to our steel and aluminum industry".
"We are heading for a trade war, which is going to be all losers - there will be no winners". They must open their markets and take down their trade barriers!
He told Radio 4's Today programme: "The president has said that he believes he could win a trade war, we think that a trade war is in nobody's interests". "It's Donald Trump's failure to understand the implications for the U.S. and world economy of his isolationist policies".
Speaking on the sidelines of a meeting of finance ministers and central bankers of the Group of Seven ― the world's seven leading economies ― European Commission Vice President Valdis Dombrovskis told Reuters such an approach made it tougher to bring China in line.