The conflict in the area caused a harsh reaction from Turkey. Turkish Prime Minister Tansu Çiller announced that any Armenian advance on the main territory of Nakhchivan would result in a declaration of war against Armenia. Russian military leaders declared that "third party intervention into the dispute could trigger a Third World War". Thousands of Turkish troops were sent to the border between Turkey and Armenia in early September. Russian military forces in Armenia countered their movements by increasing troop levels along the Armenian-Turkish frontier and bolstering defenses in a tense period where war between the two seemed inevitable. The tension reached its peak, when Turkish heavy artillery shelled the Nakhchivan side of the Nakhchivan-Armenian border, from the Turkish border for two hours. Iran also reacted to Armenia's attacks by conducting military maneuvers along its border with Nakhchivan in a move widely interpreted as a warning to Armenia. However, Armenia did not launch any further attacks on Nakhchivan and the presence of Russia's military warded off any possibility that Turkey might play a military role in the conflict. After a period of political instability, the Parliament of Azerbaijan turned to Heydar Aliyev and invited him to return from exile in Nakhchivan to lead the country in 1993.