US Senator John McCain has attacked President Donald Trump after he threatened to impose new tariffs on Canada and rejected a joint communiqué issued at this weekend's G7 summit.

Axar.az reports citing AP.

On Saturday, Trump tweeted that he had instructed US officials not to endorse the communiqué during the summit in Quebec.

The US president retracted his initial endorsement of the joint statement following "false statements" by Canadian Prime Minister Justin Trudeau. At a news conference, Trudeau said Canada would move forward on July 1 with retaliatory tariffs to answer for Trump's "illegitimate" tariffs on aluminum and steel.

Hours later, McCain said in a tweet that Americans would continue to stand with US allies and support free trade regardless of Trump's position.

Meanwhile, members of Democratic leadership also took a sharp jab at Trump for reversing his endorsement of the joint communiqué.

Senate Minority Leader Chuck Schumer criticized Trump’s earlier calls for Russia to be reinstated in the group.
ouse Minority Leader Nancy Pelosi also chided Trump for “standing up for Russia and alienating our allies at the G7.”
Tensions were running high between Trump and the other world leaders over the recently implemented US tariffs on steel and aluminum imports that the president imposed on key allies, including Canada.

Trump claimed America had been obliged to levy the metal tariffs as it has been exploited as the world's "piggy bank" under existing arrangements, but his counterparts were equally determined to protect "rules-based" international trade.

The US president had also slammed America's Western trading partners, saying "all of these countries have been taking advantage of the United States on trade."