In World War II, the two sides are referred to in English as the Allied Powers (US, Britain, etc.) and the Axis Powers (Germany, Japan, etc.), often shortened to the Allies and the Axis.
A British speaker during World War II could correctly have referred to "Germany's allies". It's just that when speaking of allies without further restriction, the assumption is that you're referring to your own allies.
It would be odd to fail to include the USSR in the grouping of "the Allies" in the context of World War II. I'd like to see the context on that in order to answer it better.