BELGRADE, Serbia — Thousands of Serbs protested outside President Aleksandar Vucic’s official residence in the capital, Belgrade, on Sunday to push for greater press freedom and free and fair elections, an intensification of rallies that have been held every weekend for more than three months.

Demonstrators broke into the state-run television network’s building on Saturday to express their anger at what they said was scant coverage of their protests.

Mr. Vucic won a commanding victory in the 2017 presidential election and critics say he has used that dominance to turn the levers of state — the news media, law enforcement and the courts — against his opponents.