Donald Trump unleashed his fury on NATO Secretary General Jens Stoltenberg on Wednesday for defending Germany's energy partnership with Russia and threatened Berlin with U.S. action over the deal that he said is wholly inappropriate. 

Trump fumed that 'Germany is a captive of Russia' and said the U.S. would 'have to do something' in light of the pipeline deal that's funneling billions into Moscow's economy.

'Germany is totally controlled by Russia,' he charged. 'I think its a very bad thing for NATO,' Trump said.

Stoltenberg reminded that the U.S. and Europe are 'stronger together than apart' and that has been proven by two World Wars and the alliance's dealings with Russia. Trump told him in response, 'No, you're just making Russia richer. You're not dealing with Russia, you're making Russia richer.'

The confrontation stunned the leaders' senior advisers, including Trump's secretaries of defense and state. A press aide demanded the media leave the room as Trump pushed Stoltenberg to explain how the U.S. is supposed to protect Germany when it's opening its front door to Vladimir Putin.

The White House subsequently said that Trump would hold private talks in the afternoon on the sidelines of the NATO summit with German Chancellor Angela Merkel and French President Emmanuel Macron. 

Stoltenberg inadvertently whipped up the U.S. president at an internationally broadcast breakfast by asking him about his upcoming meeting with Putin. Trump responded with another tirade on Germany and its weaknesses while griping again about lagging contributions from member nations to the NATO alliance.

Trump gave Stoltenberg an earful with media present, telling the visibly startled NATO chief, 'We're protecting Germany. We're protecting France. We're protecting everybody, and yet, we're paying a lot of money to protect.'

Trump said that past presidents did not confront America's allies because they did not want to meddle in their affairs or they were blind to the problem. 

'I think that these countries have to step it up — not over a 10-year-period — they have to step it up immediately,' Trump demanded. 'Germany is a rich country. They talk about they're gonna increase it a tiny bit by 2030. Well, they could increase it immediately tomorrow and have no problem.'

The United States' more than 4 percent GDP contribution to the security group compared to its European allies is 'very unfair' to the American taxpayer, he said in a familiar complaint. 

'I don't think it's fair to the United States, so we're going to have to do something, because were not gonna put up with it. We can't put up with it, and it's inappropriate,' Trump proclaimed .'So we have to talk about the billions and billions of dollars that's being paid to the country that we're supposed to be protecting you against.'

Trump began the rant by telling Stoltenberg it's 'very sad' when Germany, France and 'numerous of the countries go out and then make a pipeline deal with Russia' and then expect the U.S. to foot the bill for their security.

'So we’re supposed to protect you against Russia but they’re paying billions of dollars to Russia, and I think that’s very inappropriate,' Trump said. 'And the former chancellor of Germany is the head of the pipeline company that’s supplying the gas.'

Trump informed Stoltenberg that 'Germany will have almost 70 percent of their country controlled by Russia with natural gas' when the deal is fully realized.

'So you tell me is that appropriate?' he said. 'I mean I’ve been complaining about this from the time I got in. It should never have never been allowed to have happened.

'But Germany is totally controlled by Russia, because they will be getting from 60 to 70 percent of their energy from Russia and a new pipeline. And you tell me if that’s appropriate, because I think it’s not. And I think it’s a very bad thing for NATO, and I don’t think it should have happened, and I think we have to talk to Germany about it.'

In bringing up the gas deal, Trump returned to an issue he has raised before his trip that seeks to both put Germany on the defensive while simultaneously pushing back on the narrative that it is the U.S. that is cozying up to Moscow.

In March, Germany reached a deal to allow Russian state-owned energy giant Gazprom to run its Nord Stream 2 pipeline through its waters. The 9.5 billion pound deal immediately outraged East European allies. 

Russia has used its oil and gas to pressure and punish its neighbors. The move came just a day after Germany joined UK in protesting the poisoning of former Russian spy Sergei Skripal and his daughter in Great Britain.

The pipeline will send Russian oil and gas to Germany under the Baltic Sea. Poland and other Eastern European countries fear the pipeline could leave them vulnerable to Russian pressure.

This May, a State Department official weighed in against the project. Deputy Assistant Secretary Sandra Oudkirk said the pipeline could allow Russia to exert ‘malign influence’ in Europe. But the pipeline company said the project wouldn’t be used to blackmail other countries. 

Stoltenberg unequivocally said at a news conference that followed his meeting with Trump that the pipeline deal is 'a national decision' and 'its not for NATO to decide.'

'It's not for NATO to solve this issue,' he stated.

Trump bashed Germany over the pipeline issue at a campaign rally last Thursday in Montana, where he also raised the pipeline issue. 

‘They go out and make a gas deal, oil and gas, from Russia, where they pay billions and billions of dollars to Russia. They want to protect against Russia and yet they pay billions of dollars to Russia, Trump said then.

He said at the rally that he told German Chancellor Angela Merkel that he could not ensure he nation's security as a result. 

Germany's defense minister told CNBC after Trump's assault on her country on Thursday that two weeks ago she had occasion to visit the United States and was reassured by her conversations with American lawmakers of the strength of the alliance.

'The president is as the president is. We know him and we can cope with that,' Ursula Gertrud von der Leyen told CNBC from outside of NATO's headquarter. 'This rhetoric also leads us to remember that a lot is at stake.'

Von der Leyen said that generations that came of age after WII have taken peace granted. 'Now, we have to fight for democracy. We have to secure our international order, our peace architecture,' she said. 

It was Trump who had arrived in Brussels on the defense on Tuesday after the EU Council's head berated him at an off-site event that was attached to the NATO summit.

Trump had signaled in early morning tweets on Tuesday that foreign leaders could expect a reckoning when he sees them this week in Brussels at the NATO summit over the 'unfair' burden on the U.S. taxpayer to pay for Europe's protection.

He was met with an immediate brush-back from European Council chief Donald Tusk, who said at a signing of a joint declaration between the Brussels-based security alliance and the body of EU nations, that Trump should be more careful with his taunts.

'America does not have and will not have a better ally than Europe. Today Europeans spend on defense many times more than Russia and as much as China,' he said in remarks that were addressed to Trump.  'And I think you can have no doubt, Mr. President, that this is an investment in common American and European defense and security.'

Then, in the toughest challenge yet to the U.S. president, Tusk said: 'America: appreciate your allies. After all you don’t have that many.'

Read more on dailymail.co.uk.