Suspected Falun Gong members are often arrested

On Thursday about 40 other Westerners were rounded up by police after demonstrating in Tiananmen Square with banners reading: "Falun Gong is good!"

Mr Rhodes, a freelance camera assistant from Isleworth in west London, told BBC News Online the four had planned to join the protest against the treatment of members of Falun Gong in China.

But Mr Rhodes said that by the time the four were arrested, and questioned separately for 20 hours, they had been acting purely as tourists and had not broken any laws.

The Falun Gong movement was banned in China in 1999 as an "evil cult" that was trying to overthrow the Communist Party.

Falun Gong claims that since then more than 1,600 followers have died as a result of abuse in police custody or detention centres, a charge the government denies.

'Manhandling'

Mr Rhodes said the four had been three days into a seven-day holiday when they were arrested.

He said dozens of police had burst into their hotel room "out of the blue", pulling them out "with a certain amount of manhandling".

Westerners have been arrested and deported in several incidents

They were taken to a hotel near the airport and questioned on issues such as who had bought their flight tickets, and who had told them to visit China.

Ms Katzen said she had been threatened and told to sign a statement written in Chinese, which she refused to do.

"They coerced me, they said if I don't sign this 'we will fine you and you will get into big trouble'."

She added that they were not allowed to contact the British embassy, because they had not been formally arrested.

Ms Katzen added: "I said I wanted to contact the embassy and they said 'oh, you are not under arrest, we're just chatting to you'."

Mr Rhodes said the officers confiscated most of their possessions, including his �1,500 camcorder.

He added that he still had a bruise on his chest from a policeman's elbow, and would be trying to contact embassy officials for the return of his possessions.

Torture claim

Falun Gong, which claims millions of followers around the world, teaches meditation and exercises loosely based on eastern philosophies such as Buddhism.

It first came to public notice in China in 1992, but after attracting millions of followers it alarmed the ruling Communist party, and was banned.

Falun Gong says it is a peaceful law-abiding group, whose goals are simply improved mind, body and spirit, and spiritual enlightenment for the individual.

Since 1999 Chinese police have rounded up tens of thousands of practitioners. Many have been sent to prison without trial - a form of punishment known as "re-education through labour".

There have also been several incidents when Westerners have been expelled and deported after protesting in support of the group.