Vice President Mike Pence says European nations need to speed up plans to contribute two percent of their gross national income to NATO and encourage other member nations to do the same.

At a news conference with NATO Secretary General Jens Stoltenberg on Monday in Brussels, Pence reiterated the Trump administration's position 'that for too long, for too many' the burden of paying for NATO has 'not been shared fairly among our NATO allies.

'That must come to an end,' the vice president said.

The U.S. leader declined to make new threats to nations that don't pay up, but he warned, 'The patience of the American people will not endure.'

At a news conference with NATO Secretary General Jens Stoltenberg on Monday in Brussels, Mike Pence reiterated the Trump administration's position 'that for too long, for too many' the burden of paying for NATO has 'not been shared fairly among our NATO allies

Pence told nervous Europeans on Monday that President Donald Trump remains committed to transatlantic ties. However, NATO allies they must boost their defense spending in return.

At NATO headquarters, Pence said Trump expects NATO allies to make 'real progress by the end of 2017' towards meeting a goal they set in 2014 of raising defense spending to two percent of GDP over a decade.

Trump said last summer on the campaign trail NATO countries need to pay up or prepare to defend themselves from attacks.

His defense secretary, James Mattis, delivered another stern message at a NATO defense ministers meeting last week. Washington could 'moderate' its commitment to NATO if allies fail to pay their dues, he said.

Invoking the U.S. defense secretary again, on Monday Pence told NATO nations, 'If you don't yet have a plan -- these are my words, not his -- get one. It is time for actions, not words.'

The vice president wasn't, however, prepared to back up Trump's 'or else' style threats.

'Questions about the future we'll just leave in the future as hypotheticals,' Pence said.

But he at the same time warned that American people's patience would eventually run out.

Bringing up Trump's crusade to reform NATO on the campaign trail, Pence said, 'Frankly, it struck a very resonant chord.'

The American people are frustrated 'that as our country continues to make investments in Europe's security, we see European countries falling behind,' he said.

So far, of the 28 NATO members, only the United States, Britain, Poland, Greece and Estonia have met the two percent target.

'America will do our part but Europe's defense requires Europe's commitment as much as ours,' Pence said Monday.

So far, of the 28 NATO members, only the United States, Britain, Poland, Greece and Estonia have met the two percent target - Pence said Monday that has to end

Scores of protesters gathered in the EU quarter of the Belgian capital during Pence's visit, criticizing the Trump administration's attitude towards women, gay people and climate change.

Two female protesters went topless and carried banners saying 'Pence get out of our pants,' while another placard read 'Love Trumps Hate'.

Pence, Mattis and US Secretary of State Rex Tillerson have stuck close to established policy during their first foray into Europe despite Trump's previous pronouncements.

But they have also been left to cope with their president's unpredictable remarks, and by a growing scandal over the new White House's links to Russia.

The vice president admitted on Monday he was 'disappointed' that former US national security adviser Michael Flynn had given him 'inaccurate' information about his contacts with Russia over US sanctions before he resigned last week.

However he said he fully backed Trump's decision to accept Flynn's resignation.

Pence also defended Trump's criticisms of the media, whom the president has called 'the enemy of the American people'.

'Rest assured, both the president and I strongly support a free and independent press,' he said. 'But you can anticipate that the president and all of us will continue to call out the media when they play fast and loose with the facts.'

Capping the European trip aimed at allaying fears about the new administration's support, Pence said Washington's backing for the EU remained 'steadfast and enduring'.

'Today it is my privilege on behalf of President Trump to express the strong commitment of the United States to continued cooperation and partnership with the European Union,' Pence said after talks with EU president Donald Tusk in Brussels.

He said after the meeting with Stoltenberg that the United States understand that its economy is tied to Europe's and so it its heritage.

'Looking for ways that we could reassure this weekend leaders of the European Union of our commitment to ongoing cooperation and that maintaining that partnership in the years ahead is hopefully a resonant message that came through, and it's my great privilege to be here to deliver it,' Pence said.

European allies have been unnerved by Trump's criticism of the EU as a vehicle for Germany, his praise of Britain's decision to leave the bloc and his dismissal of NATO as 'obsolete' even as he praises Russian President Vladimir Putin.

But Pence pledged the United States would keep working with Europe to boost the world's two biggest economies, fight terrorism and defend eastern EU states against Russian encroachment.

Tusk, a former Polish premier, said that Europeans 'truly needed' the meeting with Pence and that the 28-nation bloc counted on 'wholehearted and unequivocal' US support.

'Too much has happened over the past month in your country and in the EU... for us to pretend that everything is as it used to be,' Tusk said.

Capping the European trip aimed at allaying fears about the new administration's support, Pence said Washington's backing for the EU remained 'steadfast and enduring'. He's seen today with EU president Donald Tusk in Brussels

Pence also met European Commission chief Jean-Claude Juncker, a former Luxembourg premier, who stressed that the United States 'needs a strong united Europe.'.

Pence's visit came two days after Trump referred, during a rally in Florida, to a non-existent Swedish terror incident and urged people to 'look at what's happening in Brussels' as he listed a series of European cities struck by deadly terror attacks.

Pence said the United States would remain 'full partners' with the EU in fighting terrorism, a Trump priority.

He also pledged it would defend Europe's 'territorial integrity' and said the Trump administration will 'continue to hold Russia accountable' for the violence in eastern Ukraine and demand that Moscow honor the Minsk agreements for a ceasefire due to begin Monday.

An EU source told AFP that Pence's meeting with Tusk was 'very positive'.

'Will it allay all Europeans fears about Trump? No but it was the best we could have hoped for,' the source added.

Trump is expected to attend a NATO summit in Brussels at the end of May and he has also been invited to meet EU leaders.