Boris Pistorius, Germany’s defence minister, said: “Many countries have Patriot systems or comparable.”

“Let’s say if a country has, for instance, six Patriot systems or four and is not in the front line to the east, it can easily hand over a Patriot system,” he added in a television appearance on Tuesday.

Asked by the host whether it was a pointed criticism of Spain and Greece, Mr Pistorius replied: “We’re talking to them right now. I honestly can’t understand.”

His intervention is a sign of the struggles Berlin is failing in convincing its allies to part with the complex systems – which cost up to $1 billion each and can shoot down Russian hypersonic missiles.

Germany this month wrote to dozens of countries to appeal for more air-defence systems for Ukraine as part of a campaign to plug gaps in Kyiv’s defences.

But since the initiative’s launched, only Berlin has decided to send a Patriot system to Ukraine from its arsenal.