BEIJING (AP) — Sixteen years after the bloody crackdown at Tiananmen Square, China's grip on dissent has tightened. From religion to the media, political activism to the Internet, Hu Jintao's regime watches all — and silences any challenge to the Communist Party.

Members of non-sanctioned churches risk detention, potentially incendiary chat rooms are shut down, newspapers are kept on a short rein and employees of foreign news organizations have been arrested and accused of spying. Last month, an international conference on democracy planned for Beijing was canceled.

When Hu came to power in 2002, many had hoped that the new president might be willing to re-examine the June 4, 1989, crackdown on the Tiananmen Square pro-democracy protests. But he has refused appeals to do so.

‘‘Hu Jintao is by inclination a more authoritarian figure than (former President) Jiang Zemin,'' said Steve Tsang, a Chinese political specialist at Britain's Oxford University.

‘‘He takes a harder line against dissent than Jiang. He's much more decisive. He can see what needs to be done to maintain the regime's position and he's willing to do it.''

This week, Beijing accused a detained Hong Kong-based reporter of spying for ‘‘a foreign intelligence agency.''

Ching Cheong, chief China correspondent for Singapore's The Straits Times newspaper, was detained last month. His wife said he was trying to obtain a manuscript of a book on the late Communist Party leader Zhao Ziyang, who was purged after sympathizing with the protesters in 1989.