In 1956, the soviet union used military force to suppress an uprising in

The correct answer is Hungary

Although Hungary was not a part of the Soviet Union, it was a satellite state and it was expected for it to behave according to what the Soviet Union wanted. When they had an uprising because they wanted their own version of socialism and communism, the Soviet Union invaded and ended the uprising. They were even known for sending tanks into Hungary.

The answer is ethnic groups.