"We just want to help public broadcaster to put its own motto into effect: Your right to know everything," Boško Obradović yelled into the megaphone. The president of the right-wing national Serbian party "Dveri" was making an appearance in a rather unusual setting: the heart of the RTS building, the national radio station.

On Saturday, along with other opposition politicians and around fifty protesters, Obradović had forced his way into the building in the center of Belgrade, while hundreds more demonstrated outside. The riot police only managed to eject them some hours later. Isolated beatings of demonstrators were caught on camera, but the situation didn't escalate any further.

The timing of the demonstration was symbolic: RTS broadcasts its evening news at 7.30 p.m. The program traditionally has high ratings, but its millions of viewers rarely, if ever, get to see anything of the protests taking place in more than 90 Serbian cities. Since December, tens of thousands of people have been taking to the streets to protest against the "dictatorship" and in favor of the rule of law, media freedom, and free elections.

Read more: Tensions escalate in Belgrade after breach of public TV station 

Vucic remains defiant

"I'm not afraid. I can only lose my life. I will continue to fight for Serbia; that‘s the most important thing," Serbia's strong man Aleksandar Vucic responded, in his customary melodramatic tone. The president described the opposition politicians as "thugs" and "fascists" who wanted to take power by force.

As Vucic was giving a press conference on Sunday, thousands of people surrounded the presidential palace, protesting noisily against him with music, whistling, and shouting. The demonstrators broke through police lines to bring the truck with the loudspeakers up alongside the building. There were violent clashes. "As you can see, the situation is changing rapidly,” the left-wing opposition politician Borko Stefanovic told the DW reporter at the scene.

Originally, the plan was for people from all over the country to gather in Belgrade for a mass rally on 13 April, but this could be brought forward. "Hopefully this government still has some sense, and hopefully our demands will soon be met,” said Stefanovic. It was an attack on him in December that triggered the protests: Stefanović and two colleagues were beaten up before an event by men rumored to have been close to the government.

Read more: Tenth round of anti-Vucic protests held in Belgrade 

Opposition is taking shape

Although many demonstrators still refuse to support a specific opposition group, the "Alliance for Serbia" is gradually establishing itself as the primary motivating force of the protests. A wide range of people is part of the Alliance, from nationalists to the bourgeoisie to left-wing politicians.

The mass protests have proved the biggest challenge yet for Vucic, who has ruled the Balkan country with an iron fist for seven years. The list of accusations against him is a long one: nepotism, links to organized crime, clientelism on behalf of members of his Progressive Party. Of Serbia's seven million citizens, one in ten is a member of this party. The party book is seen as a passport to jobs, and a guarantor of gifts at election time.

Vucic has also splintered the political opposition by streamlining the media landscape. Apart from one cable station and a few low-circulation weekly newspapers, the mainstream media flatter their president by alternately praising him and taking aim at his critics.

Read more: Serbian PM praised at home after heated DW exchange 

Protests in Berlin

"Vucic is obviously extremely annoyed that the protests have been going on for so long", says the Belgrade-based political scientist Boban Stojanovic. Above all, he says, the president must be careful not to supply images of police brutality. This would give the demonstrators a victim status, and the situation could get out of hand. "But if the opposition ramps up the pressure even more, it could finally result in the liberation of the media, more democracy, and, hopefully, free elections," Stojanovic said in an interview with DW.

Vucic, a former nationalist hawk, rejects all the accusations against him. He wants to be the one to take his country into the EU. Many believe he could even settle the decades-old conflict with the former Serbian province of Kosovo, which is still not recognized by Belgrade as an independent state. A common theory in Serbia is that Vucic is buying the EU's silence on his domestic repression with this indication that he might make concessions on the Kosovo issue.

On Saturday there was also a demonstration in Berlin for the first time, to draw attention to this. Around fifty people gathered on Alexanderplatz in the rain in support of their fellow countrymen. "We want the citizens of Berlin to ask their political representatives why they're supporting an autocratic regime,” said Ljubica Sljukic Tucakov. The young linguist, who has been living in the German capital for six months, helped to organize the protest there. They plan to keep on demonstrating in Berlin, like in Belgrade.

There is currently unrest in a number of areas in the western Balkans. Thousands of people have also been protesting on the streets of Albania, Montenegro, and the Serbian autonomous republic in Bosnia, demanding more democracy. Some observers are already talking about a "Balkan Spring.”