A German television crew said it had to be rescued by Chinese armed police after it was attacked and detained for nine hours while filming near a chemical factory earlier this week.

Broadcaster ARD said angry workers shouted "kill the foreign spies" as the four-person team was held at the Do-Fluoride plant near Jiaozuo in Zhongzhan county, Henan province.

Reporter Christine Adelhardt said security guards detained them as they filmed a story on pollution outside the factory.

Local police tried to protect them as angry workers gathered outside the factory canteen, where they were being held, but were overrun when the crowd stormed the building.

The workers attacked the team, seized the camera and took the tape, but did not let them go. The camera was later handed back.

The German crew escaped only when a team of armed police arrived to escort them off the premises, saying later: "Factory officials appeared to have misinformed workers and agitated against us.

"We were considered spies who had tried to gather intelligence regarding Do-Flouride's technology."

People reached at the factory would not give their names but confirmed to Associated Press that the German crew had been there and repeated the spying claims. Police and local government officials referred queries to a number that rang unanswered.

Last month, Japan's Asahi Shimbun newspaper lodged a complaint with the Chinese government after one of its reporters was beaten while covering an environmental protest in Nantong, Jiangsu province.

The newspaper said Atsushi Okudera was attacked while taking pictures of demonstrators under attack by police. His camera was seized by police and 15 to 20 officers surrounded him, shoved him to the ground and kicked him, it added. They did not return his camera.