US Secretary of State Marco Rubio said Tuesday that Washington may reassess the value of the NATO alliance after the Iran war, citing growing frustration with allies’ reluctance to support the American military campaign.

“After this conflict is concluded, we're going to have to reexamine that relationship. We're going to have to re-examine the value of NATO and that alliance for our country,” Rubio said during an interview with FOX News.

“Ultimately, that's a decision for the president to make,” he added.

He criticized NATO allies for denying US requests to use military bases, saying: “We're not asking them to conduct airstrikes. When we need them to allow us to use their military bases, their answer is ‘No.’ Then why are we in NATO?”

Rubio, who said he had long been “one of the strongest defenders of NATO,” noted the alliance had allowed the US to project power globally through bases in Europe.

But he warned that the alliance risks becoming “a one-way street.”

“Why do we have… all these American forces stationed in the region if in our time of need we're not going to be allowed to use those bases?” he said.

His remarks come as several European allies have rejected or limited US requests tied to the Iran war, including denying access to bases and airspace over concerns about the legality of the war and lack of NATO consultation.

Italy recently refused a US request for aircraft to land at a military base in Sicily, while Spain has declined to authorize the use of its bases or airspace for operations related to the war. Other allies, including the UK, France and Germany, have limited their role to defensive support for regional partners and have repeatedly called for de-escalation.