October 7, 1991 – Yugoslav planes attack Zagreb

On October 7, 1991, Yugoslav Air Force planes attacked a
number of targets in the Croatian capital Zagreb,
the most significant being the Banski dvori, the official residence of the
President of Croatia. Inside the building at the time of the raid were Croatian
President Franjo Tudman, Yugoslavian President Stjepan Mesic, and Yugoslavian
Prime minister Ante Markovic, all of whom were not injured in the attack. President
Tudman laid the blame for the attacks on the Yugoslav military, but the latter
denied any involvement, instead accusing the Croatians of staging the attacks
as a ruse. The following day, October 8, the three-month moratorium on Croatian
independence (Croatia had declared independence on June 7, 1991) lapsed, and Croatia cut all ties with Yugoslavia. During the interim
period, increasing tensions had broken out into fighting in the Croatian War of
Independence.

(Taken from Croatian War of Independence – Wars of the 20th Century – Volume 2)

Ethnic Serbs in Croatia formed the majority population in Northern Dalmatia, Lika, and parts of Western Slavonia and Eastern Slavonia.

Background By the late 1980s, Yugoslavia was faced with a major political crisis, as separatist aspirations among its ethnic populations threatened to undermine the country’s integrity (see “Yugoslavia”, separate article).  Nationalism particularly was strong in Croatia and Slovenia, the two westernmost and wealthiest Yugoslav republics.  In January 1990, delegates from Slovenia and Croatia walked out from an assembly of the League of Communists of Yugoslavia, the country’s communist party, over disagreements with their Serbian counterparts regarding proposed reforms to the party and the central government.  Then in the first multi-party elections in Croatia held in April and May 1990, Franjo Tudjman became president after running a campaign that promised greater autonomy for Croatia and a reduced political union with Yugoslavia.

Ethnic Croatians, who comprised 78% of Croatia’s population, overwhelmingly supported
Tudjman, because they were concerned that Yugoslavia’s
national government gradually had fallen under the control of Serbia, Yugoslavia’s largest and most
powerful republic, and led by hard-line President Slobodan Milosevic.  In May 1990, a new Croatian Parliament was
formed and subsequently prepared a new constitution.  The constitution was subsequently passed in
December 1990.  Then in a referendum held
in May 1991 with Croatian Serbs refusing to participate, Croatians voted
overwhelmingly in support of independence. 
On June 25, 1991, Croatia,
together with Slovenia,
declared independence.

Croatian Serbs (ethnic Serbs who are native to Croatia) numbered nearly 600,000, or 12% of Croatia’s
total population, and formed the second largest ethnic group in the
republic.  As Croatia
increasingly drifted toward political separation from Yugoslavia, the Croatian Serbs
became alarmed at the thought that the new Croatian government would carry out
persecutions, even a genocidal pogrom against Serbs, just as the pro-Nazi
ultra-nationalist Croatian Ustashe government had done to the Serbs, Jews, and
Gypsies during World War II.  As a
result, Croatian Serbs began to militarize, with the formation of militias as
well as the arrival of armed groups from Serbia.

Croatian Serbs formed a population majority in south-west Croatia
(northern Dalmatian and Lika).  There, in
February 1990, they formed the Serb Democratic Party, which aimed for the
political and territorial integration of Serb-dominated lands in Croatia with Serbia
and Yugoslavia.  They declared that if Croatia wanted to secede from Yugoslavia, they, in turn, should be allowed to
separate from Croatia.  Serbs also interpreted the change in their
status in the new Croatian constitution as diminishing their civil rights.  In turn, the Croatian government opposed the
Croatian Serb secession and was determined to keep the republic’s territorial
integrity.

In July 1990, a Croatian Serb Assembly was formed that
called for Serbian sovereignty and autonomy. 
In December, Croatian Serbs established the SAO Krajina (SAO is the
acronym for Serbian Autonomous Oblast) as a separate government from Croatia in the regions of northern Dalmatia and Lika. 
Croatian Serbs formed a majority population in two other regions in Croatia, which they also transformed into
separate political administrations called SAO Western Slavonia, and SAO Eastern
Slavonia (officially SAO Eastern Slavonia, Baranja, and Western
Syrmia).  (Map 17 shows
locations in Croatia
where ethnic Serbs formed a majority population.) In a referendum held in
August 1990 in SAO Krajina, Croatian Serbs voted overwhelmingly (99.7%) for
Serbian “sovereignty and autonomy”.  Then
after a second referendum held in March 1991 where Croatian Serbs voted
unanimously (99.8%) to merge SAO Krajina with Serbia, the Krajina government
declared that “… SAO Krajina is a constitutive part of the unified state
territory of the Republic
of Serbia”.