By Francis Markus BBC Shanghai correspondent

Chinese state media have angrily denounced what they say was the hijacking late last month of nationwide satellite television signals by the Falun Gong spiritual movement.

China says messages from Falun Gong, which was outlawed by Chinese authorities in 1999 after a mass protest in Tiananmen Square, cut into broadcasts of the World Cup final for viewers in remote and rural areas.

One front page newspaper headline ran: "Falun Gong is the common enemy of humanity".

He is sleeping in his office so he can have instant access if anything unexpected happens

TV engineer, on Minister Xu Guangchun of the State Administration of Radio, Film and Television

It is a measure of official fury at what appears to be one of the more audacious acts by the outlawed spiritual movement to get its message across.

Chinese state media say that what they call the hijacking of television signals to broadcast Falun Gong messages happened late last month during the World Cup finals and events to mark the fifth anniversary of Hong Kong's handover to China.

But it is only this week that the story has been reported in major state media, a measure perhaps of the extreme sensitivity of the issue.

Chinese alarm

Official reports say that TV signals broadcast by Falun Gong illegally cut into transmissions of China's central and provincial networks via the Sino Satellite, or Sinosat.

Founder Li Hongzhi now lives in the US

The action is said to have affected viewers in remote and rural areas.

The Falun Gong movement has not claimed responsibility for hijacking the broadcasts.

Representatives in New York, where the movement's founder Li Hongzhi is based, say a series of incidents earlier this year, involving hacking into local Chinese TV stations was the work of grassroots followers.

But satellite experts say that to hijack a national satellite television beam requires access to either an earth station, from which signals are beamed up to satellites, or at the very least a very big satellite dish.

This latest incident has clearly caused considerable alarm among Chinese authorities, with one report saying the head of the state radio and television administration is sleeping in his office to prevent such an episode from happening again.