If Serbian President Aleksander Vucic hoped the resignation of his hand-picked prime minister would get students to end nearly three months of anti-corruption protests, he didn't have to wait long for an answer.

Hours after Milos Vucevic stepped away Tuesday from his role leading the country's government, thousands of protesters poured into the streets of Serbia's second-largest city, Novi Sad, to resume their calls for political change that have seriously shaken Vucic's decadelong populist rule for the first time.