NATO allies were divided Thursday on how soon, if ever, they could spend 5 percent of their national income on defense as President Trump has demanded, but the Pentagon chief confidently predicted “we’ll get them there,” potentially as soon as this month.

Torn between protecting against Russian aggressions and other spending priorities, defense officials from across the military alliance signaled at a meeting in Brussels that any agreement would be left to the leaders of NATO’s 32 member states when they meet in The Hague at the end of June.

The American defense secretary, Pete Hegseth, said there was “almost near consensus” Thursday within the alliance to boost military spending to 5 percent of each nation’s gross domestic product, up from 2 percent now. Mr. Trump has threatened to weaken American support for European security if allies do not shoulder more of the costs.

“There are a few countries that are not quite there yet,” Mr. Hegseth told reporters at NATO headquarters in Brussels. But, he said, “we’ll get them there.”

“When you consider the threats that we face, the urgency in the world, it’s critical,” Mr. Hegseth added.

The United States spends about 3.4 percent of its G.D.P. on defense but, as the alliance’s largest power, that amounts to far more money than any other NATO member. While Mr. Trump has proposed spending $1.01 trillion on defense for the fiscal year that begins in October, such spending would have to rise an additional $200 billion for the United States to reach the 5 percent benchmark, according to a recent estimate by the Peterson Institute for International Economics.