Poland is sending Soviet-era warplanes to Ukraine which has been asking North Atlantic Treaty Organization members for fighter jets to defend against Russian missile attacks.

Polish President Andrzej Duda on Thursday said Warsaw would deliver an initial batch of four MiG-29s after Kyiv’s repeated appeal for American F-16s had been ignored by Washington.

While outdated, Duda said the MiGs are the “jets that Ukrainian pilots can operate today without any additional training,” Agence France-Presse reported.

Ukrainian Air Force spokesperson Yuriy Ignat said the MiGs will help strengthen their capabilities, but they still need F-16s.

NATO member Poland’s announcement on the MiG -29 for Ukraine follows the arrest of foreign spies who reportedly installed cameras on highways and railways used in delivering Western weapons to Ukraine.