British officials are investigating reports that two Britons have been detained in China after unfurling Tibetan flags and two banners outside the Olympic stadium in Beijing, the British Embassy in Beijing said today.

British officials are investigating reports that two Britons have been detained in China after unfurling Tibetan flags and two banners outside the Olympic stadium in Beijing, the British Embassy in Beijing said today.

The protest group Students for a Free Tibet said four Tibet activists from Britain and the United States were detained in Beijing today after displaying two 140-square-foot banners outside the Olympic stadium.

The first read: "One World, One Dream: Free Tibet" in English, and the second: "Tibet Will Be Free" in English and "Free Tibet" in Chinese.

A spokesman for the British Embassy said it was aware of reports that two British nationals had been detained and officials were in touch with the Chinese authorities.

The protest happened hours before the Olympic Torch was due to arrive in Tiananmen Square, and two days before the Olympics opening ceremony takes place at the stadium.

The British Embassy spokesman said: "We are aware of reports of two British nationals being detained near the national stadium in Beijing.

"We are in touch with the Chinese authorities and are requesting immediate consular access should this information be correct."

The Free Tibet 2008 website said the two Britons arrested were Iain Thom, 24, from Edinburgh and Lucy Marion, 23, who grew up in Cambridge and now lives in London. The pair were arrested at 7am local time (midnight BST).

Mr Thom is grassroots co-ordinator for Students for a Free Tibet UK (SFT-UK) and has just finished working for Friends of the Earth Scotland, according to the website.

Ms Marion recently graduated from Bristol University. The website states she visited Tibet in 2003 and has since been dedicated to standing in solidarity with Tibetans in their struggle for freedom and human rights.

The website names the two Americans as Phill Bartell, 34, from Boulder, Colorado and Tirian Mink, 32, a project manager from Portland, Oregon.

Students for a Free Tibet said Mr Thom and Mr Bartell were arrested after scaling 120ft high streetlights near the Bird's Nest stadium to unfurl their banners. Mr Thom's read: "One World, One Dream, Free Tibet."

The organisation says the activists were detained by Chinese authorities after displaying their message for nearly an hour and their current whereabouts were unknown.

Lhadon Tethong, executive director of Students for a Free Tibet, described the four as "brave young activists".

She said: "For years, the Chinese government has tried to use the Olympics to legitimise its illegal occupation of Tibet.

"At this very moment, Tibetans are facing the most severe and violent repression they have seen in decades at the hands of the Chinese government, and we have taken non-violent action at this critical time to draw the world's attention to the crisis gripping Tibet."

Students for a Free Tibet made headlines on August 7 last year when an international team of activists unfurled a large banner on the Great Wall of China, in a bid to overshadow the official one-year countdown to the Beijing Olympics.

The organisation claims more than 200 Tibetans have been killed and thousands more have "disappeared" after a violent crackdown by Chinese authorities following protests that were started by a group of monks in the Tibetan capital of Lhasa in March.

SFT describes itself as a network of young people and activists campaigning for Tibetan independence, with 700 chapters in more than thirty countries worldwide.

SFT's international headquarters are in New York, with offices in Toronto, London, and Dharamsala, India.

Tenzin Dorjee, deputy director of SFT said: "Days before the Olympic Games begin, and as all eyes turn to China, we appeal to the world to remember that millions of Tibetans are crying out for human rights and freedom."

Mr Thom spoke by mobile telephone to ABC News, saying he entered China on a tourist visa.

He said: "I'll probably get detained by the police and then ejected out of the country but I believe it's not anywhere near the risk or the fear that Tibetans are living under the occupation of the Chinese government."

The last time Britons were arrested for similar protests in Beijing last year, they were immediately deported to Hong Kong.