Trump says US committed to NATO's mutual defense pledge

US President Donald Trump said Friday that the United States remained committed to NATO's mutual defense pledge, after he failed to endorse it in a speech in Brussels last month.

Amid worries by Washington's European partners that the US leader had not fully bought into the Atlantic alliance, Trump told reporters: "I'm committing the United States to Article Five. Certainly we are there to protect."

"That's one of the reasons that I want people to make sure we have a very, very strong force, by paying the kinds of money necessary to have that force," Trump told a joint press conference with visiting Romanian President Klaus Iohannis.

The US president stunned Europe's leaders at a summit in Brussels on May 25 when he failed to publicly back the now 29-member bloc's founding mutual defense guarantee.

Instead he castigated the allies for failing to pay their way with contributions to NATO forces, singling out especially Germany.

According to Politico, Trump's defense and security advisors included in his prepared speech a clear endorsement of the mutual defense pledge, but Trump himself struck it out just before speaking.

Doubts have remained since then, despite US diplomats and military leaders themselves restating the pledge.

- Trump to visit Poland -

Just days before his January 20 inauguration, Trump rocked the post-World War II western alliance by calling NATO "obsolete."

Article Five has been the core of the NATO treaty's strength since it was formed amid a budding Cold War with communist states -- particularly the Soviet Union -- in 1949.

It has only been invoked once -- in support of the United States, after the September 11, 2001 attacks.

On Thursday, Democrats on the House Armed Services Committee had called on Trump to declare his support for Article Five.

Trump's pledge on Friday came shortly before the White House announced that he would travel to NATO ally Poland ahead of the Group of 20 summit in early July.

"The visit will reaffirm America's steadfast commitment to one of our closest European allies and emphasize the administration's priority of strengthening NATO's collective defense," the White House said.

- 'Money pouring in' to NATO -

Speaking beside Iohannis, Trump suggested his pressure on other NATO members had had an effect.

"As you know, I have been an advocate for strengthening our NATO alliance through greater responsibility and burden sharing among member nations," he said.

"Because of our actions, money is starting to pour in to NATO.... Other countries are starting to realize that it's time to pay up. And they're doing that. Very proud of that fact."

"Because together we can confront the common security challenges facing the world," he added.

Trump praised Iohannis for boosting his country's defense spending. Romania joined the NATO alliance in 2004.

"We hope our other NATO allies will follow Romania's lead," Trump said.

Iohannis said NATO's mutual defense commitment was a crucial part of a defense against an aggressive Russia.

"In my opinion, we have to be very clear, very simple, very straightforward if we talk about Russia, and with Russia," he said.

"In my opinion, we need dialogue. But on the other hand, we need what we all together decided in NATO -- a strong deterrence."

Republican Senator Tom Cotton called Trump's explicit statement of commitment to Article Five "a good thing."

"But make no mistake: uttering magic words does not deter aggressors like [Russian President] Vladimir Putin. Only the credible threat of military force does," he said in a statement.

"And until Democrats and our European allies get serious about funding our common defense, deterrence in Europe will remain dangerously weak."

Jorge Benitez, a NATO specialist at the Atlantic Council, said Trump's statement was less than a whole-hearted commitment.

"Trump keeps using caveat: "I want people... paying the kind of money necessary to have that force," Benitez said on Twitter.