The conflict over Nagorno-Karabakh Autonomous Oblast of Azerbaijan SSR which started in early 1988 had developed unmitigated and claimed lives of many civilians , interior troops and army . Upon the initiative of the Iranian side , within the framework of diplomatic efforts on the normalization of the situation in Nagorno Karabakh and at the Azerbaijani-Armenian border , the leaders of Azerbaijan and Armenia were invited to Tehran for negotiations on May 7 , 1992 . The invitation was considered as the third stage of peace efforts initiated by Iran . First mediation stage started in February when Iranian envoy Ali Akbar Velayati visited both Baku , Yerevan and Karabakh but it was quickly halted due to capture of Khojaly and subsequent Khojaly Massacre by Armenian troops . Second effort was made in March when Iranian envoy Mahmoud Vaezi conducted '' shuttle diplomacy '' tour visiting both republics and holding several meetings which led to formal invitation of leaders of Azerbaijan and Armenia to Tehran in May
Khojaly Massacre
Khojaly Massacre
Tehran Communiqué