Poland will send four Soviet-era Mig fighter jets to Ukraine – becoming the first Nato country to send planes since Russia invaded last year.
Polish President Andrzej Duda said they would be sent in the coming days, with others handed over in the future.
Though a welcome boost to Ukraine’s air defence, the extra jets are not expected to be decisive in the war.
The deputy speaker of Ukraine’s parliament Olena Kondratyuk said she hoped more countries would follow.
Other Nato countries are planning to send the Soviet-era planes, which Ukrainian pilots are trained to fly.
Ukraine has previously asked Western countries for modern fighter jets, such as the F-16.
The UK is training Ukrainian pilots on Nato-standard aircraft. But because of the long training times, it has warned that supplying Western jets would only ever be a long-term option.
President Biden has previously ruled out sending jets from the US to Ukraine.