02 November 1936,
The Soviet boat Andreev arrived at the port of Bilbao armed. 15 fighters, 30 armoured tanks, 15 automatic guns, 200 machine guns and six guns. The armoured material was distributed on the northern front, equitably between Asturians, Cantabrians and Basques, but it caused problems in mountainous areas.
Francoist control of the roads to Vitoria was also a major obstacle to the progress in their distribution.
Source:
Sancho de Beurko Association, Russians for the Basque Army. BA-6 and FA-I armoured cars in the battle of Villarreal elDiario.es, February 13, 2020).