The expansion happened through the first world war until the mid 1960s.
Step-by-step explanation:
The major phase of the expansion can be seen as:
- Post world war 1 expansion:
when Russia had carved up a portion German and Austro Hungarian territory for itself.
- Post world war 2 expansion
This was the most massive expansion of the force of the soviets who had occupied by proxy almost all of the eastern European states as well as the Central Asian region unfed USSR.
-the Cold war phase
In this phase they were much more covert but operated in Korea, Afghanistan and many other south american nations