Russia said on Friday that all fighter jets supplied to Ukraine by Western nations would be destroyed after NATO members Poland and Slovakia pledged to send MiG-29 jets to Kyiv.
Since Russia's invasion last year NATO countries have sent billions of dollars of military aid to Ukraine, as Kyiv asks for weapons it says are vital to fend off Russian advances.
Moscow has accused the West of directly participating in the conflict through supplying weapons to Ukraine, and has warned before that NATO weapons were legitimate targets for its forces.
"In the course of the special military operation all this equipment will be subject to destruction," Kremlin spokesman Dmitry Peskov told reporters.
"It feels like all of these countries are thus engaged in the disposal of old unnecessary equipment," he said.
Slovakia ordered F-16 fighter jets from the United States in 2018 to replace its ageing MiG-29 planes. Its fleet of 11 MiG-29s was retired last summer.