BELGRADE, Serbia 

Thousands of Serbians gathered again Saturday in cities across the country in anti-government protests, demonstrations against the president and to denounce violence.

Crowds gathered for the seventh "Serbia Against Violence" demonstration in the national capital of Belgrade, Novi Sad and Nis to denounce two recent mass shootings after a demand by opposition parties.

Protesters demanded an end to the perceived promotion of violence in the media and the resignation of government ministers involved in security.

The gatherings began shortly after two mass shootings in less than 48 hours that left at least 17 dead on May 7.

Demonstrators also demanded the resignation of President Aleksandar Vucic.

Education Minister Branko Ruzic had already submitted his resignation to Prime Minister Ana Brnabic.

The crowd gathered in front of the parliament building in the capital, and marched through the city, causing traffic disruptions.

Protesters in Novi Sad held posters that read: "Everything must stop" and said they would not give up on their demands.

The crowd in Nis expressed dissatisfaction with the government.

Protesters also demanded the dismissal of the management of Serbian state TV (RTS).

As part of new measures taken by the government, 1,800 schools have been each assigned two police officers.

The process of the voluntary surrender of weapons also began Monday at Vucic’s direction.

Serbians are in shock in the aftermath of the double mass shootings that saw at least eight people killed and 14 injured when 21-year-old suspected shooter, Uros Blazic, opened fire in the town of Mladenovac, located 42 kilometers (26 miles) south of Belgrade.

And a teenage boy opened fire on a school in Belgrade, killing eight students and a security guard.