US President Donald Trump launched a stinging attack on Germany at the start of a NATO summit in Brussels on Wednesday, saying an "inappopriate" gas deal with Moscow made it a "captive" of Russia.
"Germany is captive of Russia because it is getting so much of its energy from Russia," Trump said at a breakfast with NATO chief Jens Stoltenberg. "They pay billions of dollars to Russia and we have to defend them against Russia."
"Everybody's talking about it all over the world, they're saying we're paying you billions of dollars to protect you but you're paying billions of dollars to Russia.
Trump added that "Germany is totally controlled by Russia."
Trump previously said his efforts had pushed other NATO countries to contribute more to the Western defence alliance but it was still not enough to offset the burden on US taxpayers.
"Over the last year, about $40 billion more has been given by other countries to help NATO but that's not nearly enough," Trump told reporters ahead of a NATO summit in Brussels.
"The United States is spending far too much and other countries are not paying enough, especially some.
"This has been going on for decades and it is disproportionate and not fair to the taxpayers of the United States and we're going to make it fair. I want to compliment the secretary general, he's worked very hard on this problem."
Trump told NATO allies to "reimburse" the United States for defence costs as he landed for the alliance's most difficult summit in years.
Trump touched down in Brussels aboard Air Force One hot on the heels of a stern warning from the EU's top official that America should "appreciate" its allies.
The leaders of the other 28 members of the NATO alliance are hoping for a show of unity despite stark transatlantic tensions on a host of issues, most notably Trump's repeated invective against Europe over defence spending.
He vowed not to be "taken advantage" of by the European Union, which he accuses of freeloading by relying on the United States for its defence while blocking US imports into the bloc, the world's biggest market.