A wave of nationwide protests has erupted in Serbia as tensions between the ruling Serbian Progressive Party (SNS) and the opposition group 13 August turned violent.

Clashes broke out when SNS supporters hurled firecrackers and flares at anti-government demonstrators. Interior Minister Ivica Dačić said 16 police officers and about 60 SNS supporters were injured in the unrest, adding that the violence may have been influenced by foreign powers.

Protesters are blaming government corruption for last year’s Novi Sad railway station roof collapse, which killed 16 people. The tragedy was linked to alleged shoddy construction on a Chinese-funded project. The opposition is now demanding early elections to end President Aleksandar Vučić’s 13-year rule.

The demonstrations swept through major cities, including Novi Sad and the capital Belgrade, in what has become one of the most significant challenges to Vučić’s government in years.