Nato is discussing plans to shoot down Russian missiles if they approach the alliance’s borders, Poland has claimed, after a projectile strayed into its airspace.

Andrzej Szejna, Poland’s deputy foreign minister, told a local radio station that “various concepts are being analysed within Nato … including for such missiles to be shot down when they are very close to the Nato border”.

In the firing line ... a Russian jet fires a rocket over Ukraine during a mission on Wednesday - Russian Defense Ministry Press Service

“But this would have to happen with the consent of the Ukrainian side and taking into account the international consequences,” he added.

On Sunday night, Warsaw said a Russian cruise missile fired at a target in western Ukraine had crossed about a mile into Polish airspace for 39 seconds.

Poland’s defence ministry activated air defence systems and Nato F-16 fighter jets as the object strayed over the alliance’s frontier near Oserdow, a village in an agricultural region near the border with Ukraine.

Cruise missiles are able to change trajectory mid-air to evade defensive systems.

Władysław Kosiniak-Kamysz, Poland’s defence minister, later told reporters the missile would have been shot down if there was any indication it was heading towards a target in Poland.

One defensive option on the table is to shoot down missiles before they cross from Ukraine into Nato airspace.

However, this could be used by Moscow to justify an escalation into a wider conflict beyond Ukraine’s borders.

Previous incursions into Nato airspace by Russian missiles and drones have gone unanswered, despite suggestions the alliance’s Article 5 mutual defence clause could be triggered in response to such an incident.

On Tuesday, the United States said it was ready to fulfil its Nato commitments and defend the alliance in case of an attack.

Asked about the Polish statements, Sabrina Singh, a spokesman for the Pentagon, said: “What the administration says repeatedly is that we will defend every inch of Nato. Should the Nato ally be attacked – we certainly don’t want to see that – but we will defend every inch of Nato.”