Tens of thousands marched through Belgrade on Friday in an anti-government protest following two mass shootings that killed 18 people.
The shootings have been blamed on a culture of violence that critics say authorities have allowed to fester unchecked.
On May 3, a teenage boy killed nine pupils and a security guard in the first school mass shooting in Serbia. A day later, a 21-year-old man killed eight outside Belgrade.
Opposition parties, which organised the demonstration, say the government led by President Aleksandar Vucic's Serbian Progressive Party has failed to rein in media that have promoted violence and to act against criminal elements in society.
Recent Serbian reality TV shows have featured convicted criminals including murderers and shown men beating up women.
Protesters called on Mr Vucic, Interior Minister Bratislav Gasic and the head of Serbia's security agency to resign.
“I came here to protest against living in this country, the way it is now, against violence which is visible everywhere in public speech, in media, against this evil we are living in and against the way this country is being led,” said a university professor who gave her name as Vera.
“This number of people makes me optimistic.”
Reuters estimated the protest, the third of its kind this month, drew a crowd in the tens of thousands.
The government denies the opposition parties' allegations and accuses them of organising the protests for political gain.
Mr Gasic on Friday admitted in parliament that several criminal complaints had been filed against the 21-year-old gunman but had never been processed.
In a counter-rally in Pancevo, a town outside Belgrade, Mr Vucic accused the opposition of trying to use the mass shootings for self-promotion.
“Serbia is fed up with your revolutions,” he said.
