Public transportation is shut down in the Serbian capital of Belgrade as tens of thousands of protesters converge to oppose Serbian President Aleksandar Vucic's government on Saturday.

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.