Moscow, July 11: US President Donald Trump said in an interview with the Washington Post daily that he did not want the United States to leave NATO, however, the allies had to pay their contributions.

Former White House National Security Adviser John Bolton has claimed in his recent book, 'The Room Where It Happened', that Trump wanted to threaten NATO leaders at the 2018 summit with a US withdrawal from the alliance if other NATO members did not pay contributions of 2 percent of their GDPs.

According to the former adviser, he and the US Secretary of State Mike Pompeo decided to convince the president to stay in the bloc, but, possibly reduce US contributions.

Eventually, Trump did as Bolton advised him -- declared his support for NATO -- but criticised those member states that still had small defence budgets.nIn an interview with the Washington Post's Marc Thiessen, Trump noted that even 2 percent of GDP was also 'too little'.

"I had some that were paying almost nothing, and now they're paying. And they asked me the big question: Would you leave if -- and I said, 'Yeah, I would leave.' And if you don't give that answer, they're not going to pay," the US president said, as quoted by the media outlet.

When asked whether he really wanted the US to exit NATO, Trump said, "No, I don't want to leave. But I want them to pay their fair share."

NATO states agreed in the Brussels Summit Declaration, signed in July 2014, to raise their defence spending to 2 percent of their respective GDP figures by 2024, something which a lot of allies have struggled to achieve.