On 6 September 1991, militants of the All-National Congress of the Chechen People (NCChP) party, created by the former Soviet Air Force general Dzhokhar Dudayev, stormed a session of the Chechen-Ingush ASSR Supreme Soviet with the aim of asserting independence.
Upon the Republic of Macedonia seceding in 1991, the FRY government declared Macedonia an "artificial nation" and it allied with Greece against the country, even suggesting a partition of the Republic of Macedonia between the FRY and Greece.
In September 1991, Croatian National Guard (ZNG) organised armed incursions across the Croatian border into Bosnia. ZNG opened mortar fire on Bosanska Dubica on 13 September 1991, and raided Bosanski Brod on 15 September 1991.
On September 17, 1991, General Assembly resolution numbers 46/4, 46/5, and 46/6 admitted Estonia, Latvia, and Lithuania to the United Nations, conforming to Security Council resolution numbers 709, 710, and 711 passed on September 12 without a vote.
On 20 September 1991, the JNA transferred troops to the front at Vukovar via the Višegrad region of northeastern Bosnia. In response, local Croats and Bosniaks set up barricades and machine-gun posts. They halted a column of 60 JNA tanks but were dispersed by force the following day. More than 1,000 people had to flee the area. This action, nearly seven months before the start of the Bosnian War, caused the first casualties of the Yugoslav Wars in Bosnia.
On 25 September 1991, the United Nations Security Council passed Resolution 713, imposing an arms embargo on all of the former Yugoslav territories. The embargo hurt the Army of Republic of Bosnia and Herzegovina the most because the Republic of Serbia inherited the lion's share of the Yugoslav People Army's arsenal and the Croatian Army could smuggle weapons through its coast. Over 55% of the armories and barracks of the former Yugoslavia were located in Bosnia, owing to its mountainous terrain in anticipation of a guerrilla war had Yugoslavia been invaded, but many of those factories (such as the UNIS PRETIS factory in Vogošća) were under Serb control, and others were inoperable due to a lack of electricity and raw materials.