"Twenty-three allies are going to spend two percent of GDP or more on defense this year," Stoltenberg told President Joe Biden in the Oval Office.

"NATO allies are this year increasing defense spending by 18 percent. That's the biggest increase in decades," he said.

Biden's rival in November elections, Donald Trump, has long voiced anger at NATO allies he sees as not carrying their fair share, even recently suggesting he would encourage Russia to attack them if they do not pay.

When NATO allies made the pledge at a 2014 summit, only three countries met the target -- the United States, Britain and Greece, which has longstanding tensions with neighboring Turkey.

Stoltenberg last reported that around 20 allies were meeting the target, with once hesitant nations such as Germany ramping up defense spending following Russia's invasion of Ukraine.