Protesters march in Belgrade at huge rally against Serbian president

Authorities in capital make apparent attempt to disrupt demonstration by cancelling public transport

Tens of thousands of people from across Serbia joined an anti-corruption rally in Belgrade on Saturday, in what is regarded as the culmination of months of protest that have shaken the grip of the country's autocratic president, Aleksandar Vui.

The sound of whistles and vuvuzelas echoed throughout the Serbian capital, which has been on high alert since the rally was announced.