Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

The German defense minister on Sunday pushed back on President Donald Trump’s claims that the European nation "owes vast sums of money to NATO" and the U.S., following a meeting last week between both countries’ leaders that was at times tense.

Trump tweeted on Saturday that he had a "GREAT meeting" with German Chancellor Angela Merkel the day before, but added that "Nevertheless, Germany owes vast sums of money to NATO & the United States must be paid more for the powerful, and very expensive, defense it provides to Germany!”

The president was echoing earlier statements he's made referencing the alliance's goals for defense spending during a joint press conference with Merkel on Friday.

Despite what you have heard from the FAKE NEWS, I had a GREAT meeting with German Chancellor Angela Merkel. Nevertheless, Germany owes..... — Donald J. Trump (@realDonaldTrump) March 18, 2017

...vast sums of money to NATO & the United States must be paid more for the powerful, and very expensive, defense it provides to Germany! — Donald J. Trump (@realDonaldTrump) March 18, 2017

German Defense Minister Ursula von der Leyen rejected Trump’s claim in a statement on Sunday, saying that "there is no debt account at NATO." Von der Leyen added that it was "wrong" to link the alliance’s bar for member nations to spend 2 percent of their gross domestic product on defense by 2024 to NATO alone.

"Defense spending also goes into our UN peacekeeping missions, into our European missions and into our contribution to the fight against [ISIS] terrorism," she said.

Von der Leyen said Germany wanted a fair sharing of the burden and in order for that to happen the alliance needed "a modern security concept."

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

"That includes a modern NATO, but also a European defense union as well as investments into the United Nations," she said.

Ivo Daalder, a former U.S. NATO ambassador, also dismissed Trump’s characterization, saying on Saturday "that’s not how NATO works."

"This is not a financial transaction, where NATO countries pay the U.S. to defend them. It is part of our treaty commitment," he said on Twitter.

"Those who currently don’t spend 2 percent of their GDP on defense are now increasing their defense budgets. That’s a good thing," he added. "But no funds will be paid to the U.S. They are meant to increase NATO’s overall defense capabilities, given the growing Russian threat."

German Defence Minister Ursula von der Leyen arrives to attend a foreign affair council at the European Council, in Brussels, on March 6. Emmanuel Dunand / AFP - Getty Images

"Europe must spend more on defense, but not as favor (or payment) to the U.S. But because their security requires it," he added.

Related: Trump to Merkel on Wiretaps: ‘At Least We Have Something in Common’

Trump, whose administration has had a friendlier relationship with Russia than any U.S. president in the past, has repeatedly questioned the relevance of NATO — both during and after his presidential campaign — even calling the alliance "obsolete" as recently as January in an interview with Germany’s Bild newspaper.

Merkel has been an outspoken advocate for the need to maintain NATO.

On Friday, Trump said at the press conference that he reiterated his "strong support for NATO as well as the need for our NATO allies to pay their fair share for the cost of defense."

"Many nations owe vast sums of money from past years and it is very unfair to the United States," he said. "These nations must pay what they owe."

In a closed door meeting before the press conference, Trump had reportedly pressed the German leader to increase funding for NATO and she reiterated her commitment to the 2 percent defense spending target.

Last month, the White House announced that Trump had spoken with the secretary general of NATO and agreed to join a meeting of the alliance’s leaders in Europe in late May.

Trump has been a harsh critic of Merkel in the past for their policy differences, including her handling of the Syrian refugee crisis.

And Merkel opened her remarks at the joint press conference on Friday by taking an apparent dig at Trump, saying "It's much, much better to talk to one another than about one another.”

But despite the tense moments — Trump appeared to deny a request for a handshake at one point, thought the White House says he didn't hear it — both leaders on Friday also sought to present a united front.

"Our two nations share much in common, including our desire for prosperity, security, and peace," Trump said.