Donald Trump has said he "believes in Nato" after conflicting reports he was threatening to pull the US out of the alliance.
In a press conference following a crisis meeting among Nato members, the US president said he was satisfied by members' commitment to increase spending.
He said that allies were probably worried because the US was not being treated fairly, but now it was.
“Countries are going to start upping their commitments… I let them know I was extremely unhappy with what was happening, and they have substantially upped their commitments.”
"It all came together at the end. It was a little tough for a little while."
He also sought to take full credit for what he termed an emboldened Nato.
"We have a very powerful, very strong Nato, much stronger than it was two days ago," he said.
Citing the alliance's Secretary-General Jens Stoltenberg, he said: "Secretary Stoltenberg gives us total credit, meaning me, I guess, in this case, total credit. Because I said it was unfair."
Amid rumours that Mr Trump was threatening to pull the US out of the alliance, French President Emmanuel Macron said no direct threat was issued.
Nato sources said that while Mr Trump warned that the US could "go it alone" if others didn't step up, it fell short of a direct threat to formally withdraw.
Asked if he could pull the US out of Nato without the approval of Congress, Mr Trump said: "I think I probably can, but that’s unnecessary."
On Wednesday, the US president had hinted he wanted member states to pay 4 per cent of their GDP to Nato, a doubling of the current commitments.
Speaking Thursday he seemed satisfied that he had convinced allies to meet current commitments: "right now we're getting people up to 2 per cent."
Mr Trump stressed that Nato's budget had been unfair to the United States – referring to the US having paid "90 per cent" of Nato. In reality, last year the US paid 71 per cent of the total paid toward Nato.
But now, he said, he was sure it would be fair.
Earlier on Thursday, Mr Trump’s fresh attack on Nato allies’ failure to raise defence spending prompted leaders to huddle in a special session, excluding other summit participants, sources told Reuters.
At one point, in a break with diplomatic protocol, a source said Mr Trump addressed German Chancellor Merkel by her first name and told her: "Angela, you need to do something about this."
"We had a very intense summit," Ms Merkel herself told reporters after the meeting.
Invited leaders from non-Nato countries Afghanistan and Georgia were asked to leave along with most Nato leaders' retinues of officials, as the heads of state and government of the Western alliance sought to deal with the man whose nation commands much of the budget and forces for Europe's defence.
Mr Trump had opened the first day of talks in Brussels on Wednesday with a public diatribe against Germany, the second biggest state in the Western defence alliance.
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