The rally on Saturday in the capital, Belgrade, came as protests have spread to towns around the country and have drawn increasingly insistent calls that President Aleksandar Vucic step aside.

Large crowds of flag-waving protesters converged after meeting up at several agreed-on protest venues in various parts of Belgrade, which was placed on high alert.

Tens of thousands of people have descended on Serbia's capital to protest against the deaths of 15 people in a railway station collapse. The government has put attendance at 107,000 across Belgrade. Organisers and independent monitors have yet to give their estimates.