U.S. President Donald Trump said things would get very tough with the European Union unless the bloc shapes up over trade and NATO.

"The European Union (is) treating the United States very, very unfairly on trade," Trump said at a meeting with alliance Secretary General Jens Stoltenberg in London. "The deficit for many, many years has been astronomical with the United States and Europe in their favour. I'm changing that and I'm changing it very rapidly."

"It's not right to be taken advantage of on NATO and also then to be taken advantage of on trade, and that's what happens. We can't let that happen," he added.

"When I came in, I was angry at NATO, and now I've raised 130 billion U.S. dollars," Trump said, referring to the sum Stoltenberg says Canada and European members will have added to defense budgets by next year.

"And yet you still have many delinquent - you know I call them delinquent when they're not paid up in full," he said. Only nine of NATO's 29 members spend two percent of their GDP on defense.

Trump also lashed out at President Emmanuel Macron, saying that France is "breaking off" the relationship with the NATO.

Earlier this month, Macron called NATO "brain dead" in an interview with The Economist weekly. He also expressed doubts on the applicability of the principle of collective defense, explaining that the U.S. showed signs of "turning its back" on its military allies as it had "demonstrated starkly with its unexpected troop withdrawal from northeastern Syria last month." 

He urged Europe to rethink its "strategic power" and to regain "military sovereignty."

"NATO serves a great purpose," Trump said. "I think that's very insulting," he said of Macron's comment, branding it a "very, very nasty statement essentially to 28 countries." 

"Nobody needs NATO more than France," he said. "It's a very dangerous statement for them to make." Asked whether the U.S. alliance with NATO was shaky, Trump denied it, but said: "I do see France breaking off ... I see him breaking off."

The president also expressed his views on recent hot international topics.

"The impeachment thing is a hoax, it has turned out to be a hoax. It is done for purely political gain, they are going to see whether or not they can do something in 2020 because otherwise they are going to lose," Trump told reporters.

Democrats have been looking into Trump's efforts to pressure Ukraine to investigate political rival Joe Biden, the former U.S. vice president who is seeking the Democratic nomination to face Trump in the 2020 election, and his son Hunter Biden, who was a board member of a Ukrainian energy company. 

Latest on impeachment inquiry: 

WH says it will not participate in first House Judiciary impeachment hearing

As the UK election is almost around the corner, Trump said that he did not want to interfere in Britain's election, but that he thought current Prime Minister Boris Johnson was very capable and would do a good job.

"I think Boris is very capable and I think he'll do a good job," Trump said and reaffirmed his support for Brexit.

Read more:

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"Iran is killing perhaps thousands and thousands of people right now as we speak, that it is why they cut off the internet so people can't see what is going on," Trump then commented on the situation in Iran.

"Not just small numbers which are bad, big numbers which are really bad, and really big numbers ... It is a terrible thing and the world has to be watching," he said. 

Read more:

Iran protests: 200,000 took to streets, 7,000 arrested, many killed

(With input from agencies)