NATO leader Jens Stoltenberg says he is certain that Donald Trump will maintain a strong US commitment to NATO.

NATO Secretary-General Jens Stoltenberg has reassured member states alarmed by statements from US President-elect Donald Trump that the military alliance is becoming obsolete.

“NATO is important for the stability in Europe, but stability in Europe is also important for the United States,” Stoltenberg said in a speech to a think-tank in Brussels on Thursday.

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“And I’m absolutely certain that Donald Trump … will therefore maintain a strong US commitment to NATO.”

Before the election, Trump had questioned whether the US would automatically defend its NATO allies if they came under attack.

“Either they pay up, including for past deficiencies, or we’re going to get out,” said Trump at a campaign event in Wisconsin in April.

“And if it breaks up NATO, it breaks up NATO”, he said.

Trump and Stoltenberg spoke by telephone for the first time on and agreed to look at NATO funding, the US next president’s main concern.

The military alliance includes United Kingdom, Canada, Belgium and Turkey, among others.

“The Secretary-General said that when Britain leaves the European Union, 80 percent of NATO’s budget will actually be provided by countries outside Europe,” said Al Jazeera’s David Chater, reporting from the NATO headquarters in Brussels.

“These are matters which defence analysts are saying need to be examined.”

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One analyst argued that Trump’s limited foreign policy experience means that it will be his foreign policy advisers who are going to shape the new administration’s relationship with NATO.

“This is a president-elect who comes to it without a lot of background on foreign policy,” Ian Lesser, senior director of foreign policy at the German Marshall Fund, told Al Jazeera.

“It does matter a lot who is appointed in the cabinet positions, the advisers who will shape these foreign policies.”