The Tehran Communiqué , also known as the Joint statement of the heads of state in Tehran is the joint communiqué mediated by Iranian President , Akbar Hashemi Rafsanjani and signed by the acting President of Azerbaijan, Yagub Mammadov and President of Armenia, Levon Ter-Petrossian on May 7, 1992 with an intention to end the four-year-long hostilities between Armenia and Azerbaijan over the Nagorno-Karabakh region, a former autonomous oblast of the Azerbaijan SSR .