"I wish in Europe we would start to question NATO, because NATO has only brought us more military spending and more military tensions in the world," said Ortega.

BARCELONA, Spain, June 26 (Xinhua) -- U.S. president Donald Trump's demand that NATO members spend five percent of their gross domestic product (GDP) on defense is "crazy" and will only divert funds from their welfare states, the "most important asset" of European countries, a Spanish expert said Thursday.

NATO leaders met in The Hague in the Netherlands on Wednesday to endorse the higher spending goal demanded by the United States, but Spain refused and said it would not spend more than 2.1 percent of its GDP on defense.

"It's crazy, outrageous. We have to condemn it, because whether we like it or not, it will affect the welfare states of Europe, which is precisely the most important asset that we have built in Europe since the Second World War," Pere Ortega, honorary president of Spain's Delas Center for Peace Studies, told Xinhua.

According to the political expert, NATO's overall military spending currently approaches one and a half trillion dollars and that meeting Trump's demands would mean doubling that figure to an "outrageous" three trillion dollars.

"I wish in Europe we would start to question NATO, because NATO has only brought us more military spending and more military tensions in the world. I don't want to see NATO in the future, not only confronting Russia as now, but also confronting China. That would be very sad," added Ortega, who also teaches at Spain's Open University of Catalonia.

Praising Spain as "the only country with the courage to stand up to Donald Trump," Ortega doubted whether the NATO members who accepted the target would actually end up meeting it, and he pointed out that "some countries such as Belgium and Slovakia have already said they will follow Spain's stance and will not comply."

"We have to take into account that this five percent is not for next year, it's for the next few years. We're talking about 2035, therefore, it's ten years. We'll see in ten years which European countries reach that five percent," he added.

Ortega also pointed to the inconsistency of Trump's demand because "not even the United States spends five percent of its GDP on military spending," and he added that "the United States has not committed to spending more than 3.3 percent, so acceding to this demand seems crazy to me."