Serbia held its first gay pride parade in four years on Sunday, an event that is seen as a key test of the European Union hopeful's commitment to protect minority rights.
Authorities had banned the parade after hardline nationalists attacked marchers and clashed with police at the first ever event in 2010, injuring 150 people.
Several thousand police are expected to be deployed across the capital during Belgrade Pride after threats by far-right groups ahead of Sunday's event.
Some 500 members of the ultra-nationalist Dveri group were involved in a stand-off with officers wearing riot gear in the central of the capital on Saturday night as they tried to march to parliament to protest.
Interior Minister Nebojsa Stefanovic urged calm ahead of the gay parade, warning that authorities could still stop the event if security was threatened.
The march, set to start at 1030 GMT in front of the main government building in Nemanjina Street, will pass along Kneza Milosa avenue and by parliament before ending in front of Belgrade City Hall.
Organisers were optimistic that the parade would go ahead, saying it had been met with a warmer reception than in previous years.
"For the first time the institutions have publicly supported the organisation of the pride and media reports were more favourable for the LGBT community," one of the organisers, Boban Stojanovic, told reporters on Saturday.
Planners expect a few hundred people to attend the event, and have released few details in advance due to security concerns.
Several foreign diplomats, including the head of the EU's delegation to Serbia Michael Davenport and European Parliament member Terry Reintke, said they would attend the march.
Some Serbian cabinet ministers also said they would join, including the minister for European integration Jadranka Joksimovic and Minister of Culture Ivan Tasovac.
Stojanovic cautiously welcomed the government's support, saying: "Only once the pride is held we will be sure that the support of the institutions was honest."
- 'Imposed' by Western Europe -
Others, such as Prime Minister Aleksandar Vucic, a former ultra-nationalist who has re-branded himself as pro-European, have said they will not attend.
"My obligation is to guarantee security and safety to everybody. But my choice is not to attend the parade, no way," he said.
Tensions have been running high in highly patriarchal Serbia ahead of the event.
The head of the influential Serbian Orthodox Church, Patriarch Irinej, denounced the event as "immoral" and asked why "gay sexual orientation is right to be propagated and not paedophilia and incest".
The march had been "violently imposed by a gay lobby and their mentors from (Western) Europe," he added.
Earlier this month a German LGBT rights speaker was hospitalised after being beaten in Belgrade and several ultra-nationalist groups have announced anti-gay protests over the weekend.
Dveri members were on the streets of the capital on Saturday night while another group, Obraz, called its supporters to join a march in another part of the city centre the same day.
Vucic warned earlier this week that "whoever tries to provoke incidents will be very, very severely punished".
Homophobia is widespread in Serbia and other conservative Balkan societies.
Belgrade has been under pressure to improve protection for minorities, including the LGBT (lesbian, gay, bisexual and transsexual) community, since starting accession talks with the European Union this year.