The former vice president of City University's student union was detained by Greek police alongside 18-year-old Tibetan student Tsela Zoksang who also joined the protest.

They are both American citizens and are members of the “No Beijing 2022'' campaign.

They, and a third person, entered the archaeological site as paying customers and then Zoksang and Siu climbed up some scaffolding, from which they attempted to unfurl the banner.

A security officer rushed to them and took the banner away. The two women remained on the scaffolding and deployed a Tibetan flag and a smaller banner proclaiming, "Liberate Hong Kong, revolution of the times" -- a slogan which can incite secession, according to Hong Kong court.

They also chanted slogans including “Free Tibet", "Boycott Beijing 2022'' and “No freedom, no Games.''

Police arrived and detained the protesters. The whole incident lasted about 10 minutes.

''The IOC is sending the world a message that it is ok to turn a blind eye to genocide and crimes against humanity in Hong Kong, Tibet, East Turkestan and Southern Mongolia,” Siu said in the statement from the New York-based organization Students for a Free Tibet.

The Olympic flame for the 24th Winter Games will be lit at Ancient Olympia Monday and handed over to the Chinese at a ceremony in Athens' Panathenian Stadium Tuesday.

The International Olympic Committee's Executive Board met in Athens Saturday. The board will gather at Ancient Olympia later Sunday to celebrate the 100th anniversary of the Executive Board's founding.

The dress rehearsal for the Olympic flame ceremony will also take place Sunday.

A protest against the staging of the summer Olympic Games by China previously took place in Athens in March 2008; a couple of dozen Greek and Tibetan activists tried unsuccessfully to interfere with the torch relay for that year's Summer Olympics.

The Beijing Winter Games are scheduled to run from Feb. 4-20, 2022, with the Paralympics set to follow from March 4-13.