The Derg suffered several coups, uprisings, wide-scale drought and a huge refugee problem. In 1977, Somalia, which had previously been receiving assistance and arms from the USSR, invaded Ethiopia in the Ogaden War, capturing part of the Ogaden region. Ethiopia recovered it after it began receiving massive military aid from the Soviet bloc countries of the USSR, Cuba, South Yemen, East Germany, and North Korea. This included around 15,000 Cuban combat troops.