A demonstrator gives the victory sign as workmen finish putting a drap over a huge protrait of Chairman Mao on the Gate of Heavenly Peace May 23, 1989. The demonstrators disclaim any responsibility for defacing the protrait.

Chinese police monitor a march by tens of thousands of pro-democracy protesters in the special economic zone of Shenzhen in southern China, May 22, 1989. REUTERS/Andrew Wong

Crowds of jubilant students surge through a police cordon before pouring into Tiananmen Square on June 4, 1989 during a pro-democracy demonstration. This year marks the 10th anniversary of the bloody June 4 1989 army crackdown on the pro-democracy movement at Beijing's Tiananmen Square. REUTERS/Stringer

Student leaders (L-R) Chai Ling, Wang Dan, Feng Congde and Li Lu swear to remain in Beijing's Tiananmen Square throughout June 1989. REUTERS/Bobby Yip

A captured tank driver is helped to safety by students as the crowd beats him, June 4, 1989. REUTERS/File

Residents of Beijing surround an army convoy of 4,000 soldiers on May 20, 1989 in a suburb of the city to prevent them from continuing to Tiananmen Square, where the pro-democracy students are.

Pro-democracy demonstrators pitch tents in Beijing's Tiananmen Square before their protests were crushed by the People's Liberation Army on June 3, 1989. The square, where U.S. President Bill Clinton will visit on July 27, is the heart of China's power centre with a jagged history of revolution and bloodshed.

A military helicopter drops leaflets above Tiananmen Square May 22, 1989, which state that the student protesters should leave the Square as soon as possible on Monday morning. On the third day of martial law, the troops have yet to enter central Beijing.

Hundreds of thousands of people fill Peking's central Tiananmen Square on May 17, 1989 in front of the Monument to People's Heroes and Mao's mausoleum in the biggest popular upheaval in China since the Cultural Revolution of the 1960's.

Student protesters construct a scaffold at sunset May 29, 1989, which will be used to erect the "Goddess of Democracy" in Tiananmen Square overnight. The statue is modeled aster the USA's Statue of Liberty.

An armoured personel carrier crushes one of the tents set up on Tiananmen Square by pro-democracy protestors early Sunday morning June 4, 1989. Students were later able to set fire to the vehicle before troops entered the square and opened fire. REUTERS/Stringer

Student protesters construct a tent to protest them from the elements May 26, 1989. The Gate of Heavenly Peace is in the background. The student-led protest in Tiananmen Square is in its 14th day.

A Peking citizen stands passively in front of tanks on the Avenue of Eternal Peace in this June 5, 1989, file photo taken during the crushing of the Tiananmen Square uprising. The tanks did not slow down, but they did turn around him before taking up positions in another part of the city. Chinese leader Deng Xiaoping, whose economic pragmatism transformed China but whose political authoritarianism led to the Tiananmen Square massacre, died February 19 at the age of 93.

Student protesters arriving at Tiananmen Square to join other pro-democracy demonstrators, ride pass the portrait of late chairman Mao Zedong in May 1989. REUTERS/Bobby Yip

Workmen try to drape the portrait of Mao Tse-Tung, in Tiananmen Square, China on May 23, 1989.