Serb Orthodox Church patriarch Pavle will hold a memorial service at noon for those killed in the 1995 military operation.
At Nikola Pasic Square a resolution will be read out to "most vehemently condemn the genocide committed against the Serb people of Krajina and Croatia".
Two films will be shown at the Centre for Cultural Decontamination, "Storm Over Krajina", produced by the Zagreb production company Factum, and "Return", which was filmed in 2002 by Belgrade's nongovernmental organisation Group 484 and NGOs from Croatia.
The so-called government in exile of the Republic of Serb Krajina, the unrecognised statelet established by Croatian Serb rebels in the early 1990s, announced an extraordinary session for tomorrow on the occasion of Storm's tenth anniversary.
Croatia marks Storm on August 5. In 1995 the operation liberated parts of Croatia until then occupied by rebel Serbs.