Some broke into the PTV national television’s headquarters in central Islamabad, the channel reported. It showed live footage of a crowd of men streaming into the building after breaking through its gate.
The army had been called in to restore order at the station, other channels reported.
Police fired occasional tear gas canisters at protesters outside the prime minister’s house, but were seen retreating as protesters, many carrying wooden clubs, pushed closer to Prime Minister Nawaz Sharif’s official residence.
It was not clear if he was at home at the time.
Protests led by Imran Khan, a renowned cricketer before entering politics, and fiery cleric Tahir ul-Qadri, erupted last month and descended into deadly chaos on Saturday, with at least three people killed in clashes with police.
In a nation where power has often changed hands through military coups rather than elections, the army is bound to play a key role in how the conflict unfolds but it has not directly intervened, apart from talking to the protagonists and calling on them to show restraint.