The struggle over Nagorno-Karabakh escalated after both Armenia and Azerbaijan attained independence from the Soviet Union in 1991. In the post-Soviet power vacuum, military action between Azerbaijan and Armenia was heavily influenced by the Russian military. Furthermore, both the Armenian and Azerbaijani military employed a large number of mercenaries from Ukraine and Russia. Fifteen and twenty-five hundred Afghan mujahideen participated in the fighting on Azerbaijan's side, as well heavy artillery and tanks provided to Armenia by Russia. Many survivors from the Azerbaijani side found shelter in 12 emergency camps set up in other parts of Azerbaijan to cope with the growing number of internally displaced people due to the first Nagorno-Karabakh war.