Slovakia will send its entire fleet of Soviet-era fighter jets to Ukraine to boost its defense against Russian forces, government officials said.

The eastern NATO member state will send all 13 of its MiG-29 jets – grounded since last August and in various states of readiness – at an unspecified date, Defense Minister Jaroslav Nad told reporters in Bratislava on Friday.

The announcement comes a day after Poland said it will send four Soviet-era fighter jets to Ukraine in the coming days. Both nations are responding to pleas from Ukrainian President Volodymyr Zelenskyy, who has persistently demanded warplanes since the first days of the war as essential to driving back the Russian invasion.

The deliveries would cross a threshold in sending firepower to Kyiv, as many western allies have drawn the line at delivering fighter jets, citing the risk of being drawn into a direct confrontation with Moscow.

While the aging aircraft don’t meet the standard of more modern F-16s or similar models Kyiv has craved most, MiG shipments could add to Ukraine’s fleet with operational jets or spare parts for its own damaged stock.

Officials didn’t specify when the jets, which have been grounded since a maintenance agreement with Russia was terminated last year, will be transferred to Ukraine, citing security reasons. Slovakia is awaiting the delivery of new US-made F-16 warplanes.

The nation will also send part of its Kub air-defense system to Ukraine. In return, it will receive about $700 million worth of U.S. military equipment and $200 million from European Union funds, Nad told reporters.

Last month, Nad said that Ukraine would be able to add as many as eight new planes to its fleet from Slovak hardware.

The Kremlin dismissed the plan of Slovakia and Poland on Friday, saying the fighter jets won’t be a game changer.

“You get the feeling that these countries are just getting rid of old, unneeded equipment,” Kremlin spokesman Dmitry Peskov said, according to Tass. “You don’t need to be a military expert to say that this won’t affect” the war, he added, saying that they will be “subject to destruction” by Russian forces.

The administration has been a staunch ally of Ukraine despite public opposition that has risen over the past few months of political turmoil. Prime Minister Eduard Heger defended the decision to send the jets, saying they were “not dragging Slovakia into the war.”