President Trump has already made a major, unprecedented impact in getting NATO allies to spend more on their own defense, U.S. NATO Ambassador Kay Bailey Hutchison told "Fox News Sunday."

"I've worked for three presidents, all of whom have said the same thing," Hutchison said. "Now, I think for the first time, we are really seeing the Europeans start going in the same direction. Every ally is now increasing defense spending -- we've had the largest increase in defense spending snce the Cold War."

Trump departs Tuesday on a four-nation tour amid simmering disputes over trade and military spending with fellow Western democracies and speculation about whether he will rebuke or embrace Russian President Vladimir Putin.

Trump meets the Russian leader in Helsinki as the finale of a trip with earlier stops in Belgium, England and Scotland. After meeting in Brussels with NATO leaders, who he has long pressured to spend more on their own defense, he'll travel to the United Kingdom.

WATCH: TRUMP BLAMES OBAMA FOR ANNEXATION OF CRIMEA

"He's making an impact, and the Europeans, including [German] Chancellor Angela Merkel, have said 'we need to do more, we are going to do more -- it's the right thing to do,'" Hutchison said.

"He's making an impact, and the Europeans, including Chancellor Angela Merkel, have said 'we need to do more.'" — US NATO ambassador Kay Bailey Hutchison

The U.S. NATO ambassador had some harsh words for Russia, saying their invasion of Crimea was "illegal." In June, President Trump said "we’re going to have to see" whether the U.S. would ultimately recognize Russia's annexation of Crimea.

Hutchison also said there are signs Russia is trying to sway Turkey, where President Recep Tayyip Erdogan was recently re-elected amid a sweeping government purge.

"I do think Russia is trying to flip Turkey; they're trying to flip many of our allies," Hutchison said. "They want to destablize the strongest defense alliance in the history of the world, and that's NATO."

Also on "Fox News Sunday," Republican Sen. Lindsey Graham said Russia generally couldn't be trusted.

"Russia was supposed to make sure [Syrian leader Bashar] Assad had no chemical weapons," Graham said. "I don't trust the Russians to implement any agreement when it comes to the Iranians."

Graham also echoed Hutchison's concerns about Turkey.

"Yes, they're an ally adrift," Graham said. "But it's a new chapter in Turkey's history.

"We need Turkey, and they need us," Graham added.

The Associated Press contributed to this report.