Polish President Andrzej Duda said the nation is set to hand over Soviet-made MiG-29 fighter jets to Ukraine in coming days.
"In the coming days we will first transfer, if I remember correctly, four fully operational planes to Ukraine," Duda told a news conference in Warsaw.
Duda said that Poland's air force would replace the planes it gives to Kyiv with South Korean-made FA-50 jets and American-made F-35s.
The transfer would make Poland the first NATO member to have delivered the fighter jets, as Kyiv appeals for warplanes to fight Russian forces.
Poland and Slovakia urge allies to send warplanes
Poland's leaders said last week that sending the warplanes would only be done within a larger international coalition. Slovakia has declared readiness to provide its MiG-29 planes to Kyiv too.
Polish Prime Minister Mateusz Morawiecki on Tuesday said that Warsaw could send its MiGs within weeks, but didn’t clarify whether there was any coalition ready to follow suit.
Ukraine's air force is familiar with planes and could fly them immediately without additional training.
Why MiGs are easier than F-16s
Poland's decision to send the fighter jets follows weeks in which Ukraine was appealing for the delivery of more modern Western-made fighter jets like the F-16s.
US officials on Thursday said their decision on supplying Kyiv with F-16s was unaffected by the Polish decision, with US National Security Council spokesman John Kirby telling reporters that: "It doesn't change our calculus with regards to F-16s."
Ukraine's Air Force already operates Su-24, Su-25 and MiG-29 Soviet-era fighter jets, meaning its pilots are familiar with these systems.
But, Ukrainian pilots would have to be trained to fly the planes which typically takes 9 months, and the decision would not be a practical one in the short term.
Jim Townsend, a former US deputy assistant secretary of defense for European and NATO policy, explained to DW this January why he thinks the MiGs would be a better option for Ukrainian forces in the short-term.
"They're aircraft that Ukraine has flown before and can support. And I think we need to turn to that first. And it might be, in order for those planes to be sent to Ukraine, the US could backfill with F-16s to that country that is giving up their former Soviet aircraft."
Some training underway in UK
On the other hand, while the UK promised to train Ukrainian air forces to fly combat jets in February, the UK's Royal Air Forces itself does not operate F-16s.
The UK said its decision to train pilots to fly fighter jets didn't mean it was looking to send their jets to Kyiv, rather that it wanted to be ready more quickly should a decision change in the future. Britain also noted that given Ukraine's air force equipment losses, it currently had more fighter pilots than aircraft fit to fly.
German Chancellor Olaf Scholz told the national parliament in January that Germany was clear from the very early days of war that it would not send combat aircraft.
"I made it clear very early on that we are not talking about combat aircraft, and I am doing the same here,” Scholz said.
Ukraine and Russia have lost hundreds of thousands of soldiers on both sides and Ukrainian forces are training for a spring offensive.
Fighting inBakhmut also continues to rage, as the Kremlin deploys huge resources in a bid to hold the town.
Kyiv appeals for fighter jets
Ukrainian President Volodymyr Zelenskyy in surprise visits last month to the UK, France and Brussels, home to the European Union institutions, made strong appeals for the jets.
Washington has not made any comments on whether it would give the fighter jets to Ukraine or allow other countries to re-export their own F-16 aircrafts.