NATO said on Wednesday it was prepared to respond to any threat and would take whatever action was necessary to defend its members, after a report said Iran had considered targeting US military assets in Europe if Washington escalated its war with Tehran.

A NATO official told Reuters that the alliance's deterrence and defence posture remained "strong and effective", pointing to four occasions earlier this year when NATO air defences intercepted ballistic missiles launched from Iran towards Türkiye.

The statement followed a report by the Financial Times citing people close to the Iranian government who said Tehran had examined possible strikes against US military targets in southern and south-eastern Europe. The report named Bulgaria and Cyprus among the locations considered, while also saying Iranian forces had separately discussed possible attacks on undersea fibre-optic cables in the Strait of Hormuz.

The claims have not been independently verified, and there was no indication that Iran had decided to carry out such attacks.

NATO has already strengthened its ballistic missile defence posture after Iranian missiles were intercepted while heading towards Türkiye. The alliance said in March that its forces had detected, tracked and successfully intercepted an Iranian ballistic missile, describing the incident as evidence of its ability to defend allied populations.

A fourth interception was reported by Türkiye on 30 March. Reuters reported that the missile entered Turkish airspace and was shot down by NATO defences. Iran has denied specifically targeting Türkiye during the conflict.

NATO Secretary General Mark Rutte said in March that the alliance would do everything necessary to defend every inch of NATO territory, while making clear that the US-led military campaign against Iran was separate from NATO's collective role.

The latest warning comes as US-Iran diplomacy has deteriorated. President Donald Trump said on Tuesday that there were no talks or discussions taking place or scheduled with Iran, contradicting a more positive assessment from his envoy Jared Kushner a day earlier.

Trump also said the Strait of Hormuz was open, while Iran has maintained that the waterway remains closed until conditions including an end to the US blockade and military operations are met. Shipping through the strait remains severely disrupted.

NATO's latest statement does not indicate that Article 5, the alliance's collective-defence clause, has been invoked. The immediate concern is whether the reported Iranian planning will lead to any action beyond the Middle East if the conflict escalates.