"Several recent incidents demonstrate that history and past ideologies still play a role in many people's minds in Croatia as well as in neighbouring countries," the OSCE mission's head, Ambassador Peter Semneby, was quoted by a press release as saying.
"For this reason, it is important to foster joint visions for the future, not least the European vocation of all countries in the region, which is based on tolerance and will also eventually bring greater prosperity," the ambassador added.
The OSCE mission noted a recent incident involving Serbian students, who were convicted and imprisoned for disturbing public order when they displayed the image of Chetnik leader Draza Mihailovic, a war crimes convict, while taking their pictures in downtown Zagreb.
This follows on recent conflicts around the erection of monuments commemorating Croatian leaders from the same period, the press release said.
"The OSCE (Organisation for Security and Cooperation in Europe) Mission believes that hate speech and the promotion and glorification of ideologies used to spread ethnic discord should be prevented. However, it is important that this is done in a balanced manner so as not to encroach on the fundamental right to freedom of speech," the press release said.
"Ultimately there is a need for a profound political and legislative discussion on measures to prevent hate speech and on how to assess past ideologies while safeguarding the freedom of speech," the press release read.