German air crews supported the Nationalist advance on Madrid, and the successful relief of the Siege of the Alcázar. Ultimately, this phase of the Siege of Madrid was unsuccessful. Soviet air support for the Republicans was growing, particularly through the supply of Polikarpov aircraft. Warlimont appealed to Nazi Germany to step up support. Some Nazi figures, including Göring, were opposed, but following German recognition of Franco's government on 30 September, German efforts in Spain were reorganised and expanded.