Heraldo de Madrid - Around 140,000 rally in Belgrade ratcheting up calls for elections

The rally was the largest in several months of student-led actions, which began in November after the roof of a train station collapsed in the northern city of Novi Sad, killing 16 people -- a tragedy widely blamed on entrenched corruption.

Earlier on Saturday, a sea of protesters filled Belgrade's largest square and poured into several surrounding streets.

The Independent Protest Monitor, Archive of Public Gatherings, estimated the crowd size at around 140,000, significantly higher than the police estimate of 36,000.

"We want elections!" the crowd chanted, waving Serbian flags and holding banners bearing the names of cities and towns from around the country.

For more than half a year, students have blockaded universities and organised large demonstrations around the country, demanding a transparent investigation into the deaths.

But in contrast with previous gatherings, which have remained peaceful, clashes erupted between demonstrators and riot police.

Police fired tear gas and stun grenades as protesters hurled flares at rows of police in several clashes following the huge gathering in Serbia's capital.

AFP journalists witnessed at least two people being taken into custody and local media reported multiple arrests.

'We will rally as long as it takes'

Frustrated by government inaction over the tragedy, students have been calling for elections since May.

"We show once again that we will not stop," law student Stefan Ivakovic told AFP.

"We will rally as long as it takes until the demands are met."

Ahead of Saturday's protest, organisers issued an "ultimatum" for President Aleksandar Vucic to announce elections by 9:00 pm (1900 GMT) - a demand he had rejected well before the deadline.

As the protest ended, organisers played a statement to the crowd, calling for Serbians to "take freedom into your own hands" and giving them the "green light".

"This nation does not plan to retreat, but will stand up trampled, crushed, oppressed to conquer its better tomorrow," it said.

-'Foreign powers'-

Following the clashes, the police minister "strongly condemned the attacks" on officers and said those responsible would be arrested.

Earlier, Vucic posted a photo of himself visiting nearby pro-government encampments outside the parliament building, issuing a message of support to an earlier counter-demonstration there.

But the crowd near the camps had dwindled significantly from its initial thousands.

The outcry over the Novi Sad disaster has already toppled the country's prime minister, but the governing party remains in power -- with a reshuffled government and the president at its heart.

Vucic, who had warned of violence before the rally, has repeatedly said the protests are part of a foreign plot to destroy his government.

More than a dozen people have been arrested in recent weeks, a crackdown that has now become routine ahead of large demonstrations.

On Friday, five people were remanded in custody accused of plotting to overthrow the government, according to a statement from Serbia's Higher Court in Belgrade.

'Arrests, interrogations, and attacks'

Students have also called for the removal of the pro-government encampments, warning of the "radicalisation" of the movement if their demands are not met.

"We have been with the students from the very beginning, and we will continue to stand with them," University of Belgrade rector Vladan Djokic told AFP before the clashes.

Djokic, who has become a vocal supporter of the protest movement, earlier told the crowd that students had faced "arrests, interrogations, and attacks" in the months leading up to the rally.

He said he wasn't sure if student demands would be listened to, but he expected the government to respond after the mass protest.

Earlier this month, local polls in two municipalities marked the first electoral clash between an opposition coalition and Vucic's Serbian Progressive Party.

As before, Vucic denied allegations of fraud.

O.Pardo--HdM