Secretary-General Mark Rutte has sought to downplay fears of wavering US commitment to the alliance.

NATO chief Mark Rutte has said he is “optimistic” that members will agree to a major boost in defence spending and stressed that Washington is “totally committed to the alliance”, on the second day of the organisation’s annual summit.

Leaders of the transatlantic alliance’s 32 members are meeting in the Dutch city of The Hague on Wednesday under pressure from the Trump administration to approve new targets of spending 5 percent of gross domestic product (GDP) on defence, amid swirling questions over United States President Donald Trump’s commitment to the alliance.

But, speaking before a leaders’ meeting on the second and final day of the annual summit, NATO Secretary-General Rutte insisted there was no question of Washington, NATO’s most powerful member, backing away from the alliance or its underlying principle of mutual defence.

“There is absolute clarity that the United States is totally committed to NATO, totally committed to Article 5,” he said, referring to the cornerstone collective defence principle enshrined in NATO’s founding treaty, which holds that an attack on one member is treated as an attack on all.