BREAKING NEWS: Donald Trump warns 'the horror you saw in Manchester will continue forever' if leaders do not do more to stop 'savage, barbaric' terrorist attacks - which he links to migration of 'thousands and thousands'

• Trump led a moment of silence for the victims of the bombing in Manchester
• He spoke during an unveiling of a 9/11 memorial at the NATO headquarters
• He told NATO leaders the unveiling is 'a day for both remembrance and resolve' 
• Speaking to NATO leaders, he said the US would never stop fighting terrorism
• Trump also lectured European leaders on 'unchecked flow of migrants' 

President Donald Trump told leaders of the NATO alliance on Thursday that the Manchester bombing that killed 22 earlier this week demonstrates the depths of the evils of terrorism.

After leading a moment of silence at the NATO headquarters in Brussels for victims of Monday night's bombing, Trump said that attacks will continue unless steps are taken to counter terrorism strikes.

He said that the United States would never stop fighting terrorism, calling the Manchester attacks 'savage' and 'barbaric'. 

Terrorism must be stopped or ... the horror you saw in Manchester and so many other places will continue forever,' Trump said, referring to Monday's suicide bomb in the northern English city that killed 22 people, including children. 

His comments came after he unveiled a memorial to the September 11, 2001, attacks on New York and Washington at the NATO headquarters. 

He told NATO leaders that the unveiling is 'a day for both remembrance and resolve'. 

'We will never waiver in our determination to defeat terrorism and achieve lasting security, prosperity and peace,' he said. 

Trump also lectured Nato leaders on their open borders, tying terror attacks like last week's carnage in the United Kingdom to the unchecked flow of migrants throughout Europe.

He said: 'You have thousands and thousands of people pouring into our various countries and spreading throughout, and in many cases we have no idea who they are. We must be tough, we must be strong and we must be vigilant.'

The NATO of the future must include a great focus on terrorism and immigration,' he said.

Trump hammered home the same anti-terror themes he has flogged since his inaugural foreign trip began last Saturday – saying of suicide bombers and other jihadis that 'wherever they exist in our societies, we must drive them out and never, ever let them back in.' 

Trump said he has been 'very, very direct' with NATO Secretary General Jens Stoltenberg and other nations 'in saying that NATO members must finally contribute their fair share and meet their financial obligations.'

'But 23 of the 28 member nations are still not paying what they should be paying, and what they are supposed to be paying, for their defense.'

'This is not fair to the people and taxpayers of the United States,' he said, 'and many of these nations owe massive amounts of money for past years, and not paying in those past years.'

Trump said the U.S. has spent more money on defense in the past eight years than the combined spending of