The White House has suggested that there are “clearly logistical challenges” with Poland's proposal to provide Ukraine with Soviet-era fighter jets.

"Our defense officials are in touch with Ukrainian counterparts, NATO counterparts, discussing what are clearly logistical challenges here,” White House press secretary Jen Psaki said while offering a status update Wednesday amid uncertainty over how and if to proceed with plans to send jets to Ukraine.

She pointed to a statement by Pentagon spokesman John Kirby saying the Pentagon did not consider Poland's proposal "tenable".

Kirby “made clear that obviously the proposal from yesterday, that fighter jets manned by Americans departing a NATO base to fly into airspace contested with Russia raises serious concerns for the United States and NATO,” she said. 

Psaki cited some logistical and operational challenges: getting planes into Ukraine without escalation, as well as ensuring the safe movement of aircraft in war.

She called this a "serious logistical bottleneck", saying discussions on the issue were ongoing.

Psaki noted that the US "has not held back" military aid to Ukraine, including arms, anti-missile systems and tank systems.

Poland the previous day offered to hand over all its fighter jets to the USA at its base in Germany.