In a combative start to his NATO visit, President Donald Trump asserted on Wednesday that a pipeline project has made Germany "totally controlled" by and "captive to Russia".
Mr Trump, in a testy exchange with NATO Secretary-General Jens Stoltenberg, took issue with the US protecting Germany as it strikes deals with the Russian Federation.
"I have to say, I think it's very sad when Germany makes a massive oil and gas deal with Russia where we're supposed to be guarding against them," Trump said at breakfast with Stoltenberg.
The deal with Russia
The president appeared to be referring to the Nord Stream 2 pipeline that would bring gas from Russia to Germany's northeastern Baltic coast, bypassing Eastern European nations like Poland and Ukraine and doubling the amount of gas Russia can send directly to the country.
The vast undersea pipeline is opposed by the US and some other EU members, who warn it could give Moscow greater leverage over Western Europe.
Mr Trump repeatedly described Germany as "captive to Russia" and urged NATO to look into the issue.
In the back-and-forth, Stoltenberg stressed that NATO members have been able to work together despite their differences.
"I think that two world wars and the Cold War taught us that we are stronger together than apart," he said.
However, German Chancellor Angela Merkel pushed back as she arrived at NATO headquarters for the summit, insisting Germany made its own decisions.
"I've experienced myself a part of Germany controlled by the Soviet Union and I'm very happy today that we are united in freedom as the Federal Republic of Germany and can thus say that we can determine our own policies and make our own decisions and that's very good," she said.
Why were the comments made?
The dramatic exchange set the tone for what was already expected to be a tense day of meetings with leaders of the military alliance.
Mr Trump has been pushing NATO members to reach their agreed-to target of spending two percent of their gross domestic products on national defense by 2024 and has accused those who don't of freeloading.
Whilst en route to the summit, the leader tweeted:
NATO estimates that 15 members, or just over half, will meet the benchmark by the agreed date based on current trends.