Dissidents in China detained and harassed as Beijing prepares for party congress

Government critics and activists intimidated by police ahead of Sunday's Communist party meeting, where Xi Jinping is expected to gain third term

• Everything you need to know about China's Communist party congress

Chinese authorities have stepped up surveillance and harassment of government critics as part of a crackdown on dissent ahead of the Communist party's upcoming 20th congress, its key political gathering.

Since mid-September, numerous activists and petitioners seeking to lobby the government have been detained or put under house arrest across China, while many human rights lawyers have been intimidated, harassed and followed by agents. They say authorities, wary that their criticisms of the government could lead to social discontent and threaten the regime, are pulling out all the stops to silence them ahead of the twice-in-decade event, set to start on Sunday.