Data from this archival document show how widely dispersed Spanish youth were by 1944. Starting in 1941, they were evacuated and sent to work in factories in southern and central USSR. When compared the following graph, we can see that approximately eighteen months later the Spanish youth had been re-concentrated in and around Moscow much like the Spanish children.
Qualls, Karl D., "06 Location of Spanish Youth, June 1944" (2020). Stalins Niños - Charts & Non-GIS Maps. 4.