By Aleksandar Vasovic

BELGRADE (Reuters) - Authorities in Serbia are considering banning a gay rights parade and all other public gatherings in Belgrade this weekend, fearing a repeat of violent scenes two years ago when ultranationalists tried to disrupt a similar event.

Prime Minister Ivica Dacic, who also serves as interior minister, said on Monday the planned parade - whose purpose it to call for better and more gay rights in the predominantly Serbian Orthodox Christian society - was a major security risk.

"So far we have received only partial security assessments and we may ban the parade if it proves a high-risk gathering," he told reporters.

The authorities outlawed last year's parade at the last moment for the same reason and dozens were injured the year before in violent clashes between police and ultranationalists unhappy about the event.

This year, rightists want to hold a counter-rally in the Serb capital on Saturday, the day of the planned gay parade, and have also threatened to disrupt an exhibition by Swedish artist Elisabeth Ohlson Wallin, which they say mocks Jesus Christ because it shows him in female clothes and high heels.

The exhibition, one of several events associated with the gay pride parade, is due to open on October 3. Vladan Glisic of the small ultranationalist movement Dveri said it is likely to infuriate many people who think along the same lines as him.

"The exhibition insults the feelings of believers and all religious people ... and we want a reaction from the Serbian Orthodox Church and the government," Glisic said.

Dacic, the prime minister, likened the exhibition to a recent film mocking the Prophet Mohammad that has triggered weeks of violent riots and protests throughout the Muslim world.

"Throughout the world there are problems caused by the movie and the cartoon about (Prophet) Mohammad ... yet here in (downtown) Belgrade they expect us to look at Jesus Christ shown in a homosexual context," Dacic said.

Goran Miletic, a human rights activist and one of the parade's organizers, said a ban would be a defeat in the face of intolerance. "There are threats of violence and the police must respond to that," he said.

Serbia's Socialist-nationalist government, that came to power in July, is under pressure to demonstrate its readiness to protect human rights in order to keep the country's bid to join the European Union on track.

Traditionally conservative societies across the Balkans have been slow to accept greater gay rights and similar events across the region have often ended in violence.

(Reporting by Aleksandar Vasovic; Editing by Zoran Radosavljevic and Andrew Osborn)