"To have a contentious conversation and name-call a country or the Prime minister of a country that's one of our greatest allies in Asia is foolish," said the Democratic senator from Virginia, who was Hillary Clinton's running mate in 2016.
"To suggest to the President of Mexico we may have to send US troops into Mexico is foolish. Some of the statements that the President is making about Iraq and Iran are foolish."
Kaine added, "He's doing kind of amateur-hour stuff on matters of significant national importance."
During his call Saturday with Turnbull, Trump objected to an agreement over the United States receiving refugees from Australia, sources told CNN. The deal was reached under the Obama administration,
and many of the refugees are from the seven countries affected by Trump's travel ban
During the call, Trump reportedly called the refugees "illegal immigrants" and suggested that one of them could be the next "Boston bomber." He later tweeted that the deal was "dumb.
According to an Associated Press report
, during his call Friday with Peña Nieto, Trump threatened to send US troops to stop criminals in Mexico unless the government did more to control them, but both the US and Mexican governments denied details from the story.
Trump told an audience Thursday at the National Prayer Breakfast not to worry about the reports of his phone calls with foreign leaders.
"We have to be tough. It's time we're going to be a little tough, folks," he said. "We're taken advantage of by every nation in the world virtually. It's not going to happen anymore. It's not going to happen anymore."
But on "New Day," Kaine dismissed the suggestion that Trump was simply fulfilling his campaign promises of "tough talk."
Referring to the US response to Iran's missile test this week
, "We ought to be pursuing sanctions against them in the UN for doing that," the senator said.
Kaine added that Trump's travel ban had done nothing to ease tensions with Iran and Iraq.
"He's complaining that Iran is gaining too much influence in Iraq and wants to be tough about it. But what is he doing? He said we should go in and take Iraq's oil, and he's banned Iraqi citizens, even those who have worked with our American military, from coming into the United States," he said.
Trump's statements and actions strengthen Iran, Kaine said.
"Iran is in Iraq basically saying, 'You can't trust the US, you need to trust us.' ... Donald Trump is making Iran's case for them every day," he said.
National security adviser Michael Flynn's asserted Wednesday that
the United States had placed Iran "on notice" following its ballistic missile test launch
But Kaine said he had "no idea what that means."
"There's nothing that will strengthen Iran's hand more in the region than the kind of foolish actions that the administration has taken," he insisted.