Question

why did ussr send it's army in afganistan​

Answer 1

Answer:

Soviets wanted to weaken Pakistan which was an ally of United States and China. ... Soviet Union also believed that the hostile behaviour of Afghanistan against Pakistan and Iran could alienate Afghanistan from the west and Afghanistan would be forced to into a closer relationship with Soviet Union.

Answer 2

Answer:

On December 24, 1979, the Soviet Union invades Afghanistan, under the pretext of upholding the Soviet-Afghan Friendship Treaty of 1978. As midnight approached, the Soviets organized a massive military airlift into Kabul, involving an estimated 280 transport aircraft and three divisions of almost 8,500 men each.