BELGRADE, Serbia -- Serbia's first openly gay prime minister joined several hundred activists Sunday at a gay pride march that was held amid tight security in the conservative Balkan country.

Holding rainbow flags, balloons and a banner reading "For change," pride participants gathered in Belgrade, the Serbian capital, before setting off on a march through the city. Many approached Prime Minister Ana Brnabic, greeting her and taking selfies.

"The government is here for all citizens and will secure the respect of rights for all citizens," Brnabic told reporters. "We want to send a signal that diversity makes our society stronger, that together we can do more."

Serbian riot police cordoned off the city centre with metal fences early Sunday to prevent possible clashes with extremist groups opposed to the pride gathering. Right-wing activists gathered in a central area with banners, but no conflicts were reported.

Brnabic was elected earlier this year amid Serbia's efforts to improve its image as it moves toward European Union membership. Gay rights activists in Serbia have hailed her ascension as an important step in their struggle, but say much more needs to be done.

"Today we walk together and together we will stress that problems still exist and that we want to work together to solve them," said activist Goran Miletic.

Serbia's embattled LGBT residents face widespread harassment and violence from extremists. Violence marred the first pride march in 2001, and more than 100 people were injured during an event in 2010 when police clashed with right-wing groups and soccer hooligans. Several pride events were banned before marches resumed in 2014.

Despite the hundreds of riot police stationed in downtown Belgrade and the helicopters flying overhead, activists said the atmosphere on Sunday was more relaxed than in previous years.

Brnabic attended the pride march last year when she was public administration minister in the previous government of now-President Aleksandar Vucic. A former ultranationalist who now identifies as a pro-EU reformer, Vucic has declined invitations to attend the pride march.

AP writer Jovana Gec contributed to this report.