Washington DC - Secretary of State Marco Rubio slammed Spain and other NATO members for their unwillingness to support the war on Iran, hinting at a reevaluation of US commitment to the alliance.

Rubio accused Spain of denying US use of its airspace and boasting about it, according to a transcript of remarks to Al Jazeera released by his department on Monday. He also said Washington had faced resistance in using military bases in Spain and elsewhere.

NATO is useful to the US because it allows troops and equipment to be stationed abroad, Rubio said.

"But if NATO is just about us defending Europe if they're attacked but then denying us basing rights when we need them, that’s not a very good arrangement," he added.

"That's a hard one to stay engaged in and say this is good for the United States. So all of that is going to have to be reexamined."

Rubio continued: "Let's hope we can fix it. We'll have time to address it after."

Spain recently closed its airspace to flights linked to the Iran war and had earlier barred the US from using the Rota and Morón bases in Andalusia for operations. The facilities have long been jointly operated by the two countries.

President Donald Trump has repeatedly criticized NATO allies for what he sees as insufficient support in the conflict. Article 5 of NATO's mutual defense clause does not apply to the unprovoked war launched by the US and Israel against Iran.