A leading Hong Kong university has taken down a statue from its campus site that for more than two decades has commemorated pro-democracy protesters killed during China's Tiananmen Square crackdown in 1989, Reuters witnesses said.

Late on Wednesday night, security guards at the University of Hong Kong (HKU) placed yellow barricades around the 8m-high, two-tonne copper sculpture called the "Pillar of Shame" that commemorates those killed by Chinese authorities more than three decades ago.

The artwork...