“We are looking actively now at the question of airplanes that Poland may provide to Ukraine and looking at how we might be able to backfill should Poland decide to supply those planes,” Blinken said during a visit to Moldova.

"Can't speak to a timeline but I can just say we're looking at it very, very actively," he told reporters during a visit to Moldova.

A Polish official told the Financial Times: “Poland is not in a state of war with Russia, but it is not an impartial country, because it supports Ukraine as the victim of aggression. It considers, however, that all military matters must be a decision of Nato as a whole.”

Ukrainian president Volodymyr Zelenskyy has asked the US to give Poland and other eastern European allies F-16 fighter jets, enabling those countries to then send Russian-made warplanes to Ukraine because Ukrainian pilots are trained to fly Russian-made aircraft.