Tens of thousands of people marched through the Serbian capital, Belgrade, and blocked a key bridge Friday in the second large protest since two mass shootings that rattled the Balkan country and killed 17 people, including many children.

Protesters gathered in front of the Parliament building before filing by the government’s headquarters and onto a highway bridge spanning the Sava River, where evening commuters had to turn their vehicles around to avoid getting stuck. As the demonstrators passed the government buildings, many chanted slogans decrying Serbia’s populist president, Aleksandar Vucic, whom they blame for creating an atmosphere of hopelessness and division in the country that they say indirectly led to the mass shootings.