Beijing -

An iconic portrait of former Chinese Communist Party leader Mao Zedong was damaged on Thursday in central Beijing, according to photographs published by Japan's Kyodo News.

The photographs showed workers apparently trying to clean one of several black marks from a lower part of the giant portrait, which dominates the Tiananmen, or Gate of Heavenly Peace, on the north side of Tiananmen Square.

Several attacks on the portrait have been reported since an act of defiance during pro-democracy protests in the square in 1989, when three men pelted it with paint-filled eggshells.

The Tianwang human rights website reported several protests by single legal rights petitioners at the square on Thursday, but it was not clear if the damage to the portrait was linked to any protest.

Beijing police refused to answer any questions on the incident. - Sapa-dpa