BELGRADE: Tens of thousands were expected to rally in Belgrade on Friday in support of President Aleksandar Vucic, under increasing pressure after the government's response to the mass shootings tapped into simmering anger against the ruling party.

The rally “Serbia of Hope” is widely perceived as a government response to opposition-led protests which brought tens of thousands onto the streets in one of the largest demonstrations the Balkan country has seen in decades.

“A gathering where we will try to unite Serbia and show that it has a future,“ Vucic said on in a video posted on Instagram ahead of the rally.

Vucic's supporters were arriving from Friday morning by bus and train from across Serbia, while human rights watchdogs and local media reported receiving testimonies from people who said they had been pressured into attending.

The protests against the government first took shape earlier this month following back-to-back shootings within 48 hours -- including a massacre at an elementary school in Belgrade.

Days after the shootings, tens of thousands rallied demanding a crackdown on violent content on pro-government media and the resignation of the interior minister and intelligence chief.

But the demands were met with fierce rebuttals from the president and his allies, who mocked the rallies and hurled insults at participants. Vucic announced the counter-demo billing it as “the biggest gathering in Serbian history”.

Civil society groups have meanwhile called on Vucic to scrap his rally, underlining that it would contribute to social polarisation.

“It is not a time to demonstrate strength ... It is not appropriate to spend huge resources just to create the impression that the legitimate questions and demands of citizens are not loud enough and can be drowned out by the applause of one’s supporters,“ some twenty civil society organisations said in a joint statement.

As a response to the escalated tensions, Vucic has announced an option to schedule snap elections for autumn, even though his party won a landslide win in last year's parliamentary vote.

Belgrade is braced for a tense weekend, as the opposition plans to take to the streets again on Saturday. - AFP