HONG KONG - A Hong Kong student union is holding a student vote on whether China should apologize for its crackdown on pro-democracy protesters in and around Beijing's Tiananamen Square 20 years ago in which hundreds were killed.

While China has tried to whitewash any commemoration or mention of June 4, formerly British-ruled Hong Kong has remained the only city on Chinese soil where annual June 4 vigils, remembrances and protests are tolerated.

Faced with growing student indifference, the Hong Kong University Student Union kicked off the three-day vote on whether China should rectify its verdict that the June 4 protests were counter-revolutionary and that killings were justified.

After 20 years of denial and injustice, the world has had enough, the union said in explaining the need for a referendum.

As the heirs to those who have fought and died for the freedoms which we now enjoy, we all share a duty to step forward on their behalf lest all their sacrifices be in vain.

The vote comes amid recent signs of on-campus tensions in Hong Kong between democratic-minded students and conservative elements wanting to tone down the criticism of Beijing, particularly among students from mainland China.

The demonstrations that drew more than a million people on to Beijing's streets are now a fading memory and the killings are still taboo in mainland Chinese media.

A so-called democracy wall on the University of Hong Kong's campus used to raise awareness of June 4 through photographs, essays and posters was recently vandalized.

Forums leading up to June 4 have also been proven divisive with mainland students booed when expressing views closely aligned with the Communist Party, namely that the crackdown was necessary to maintain stability.

Hong Kong is a place in China where people can still openly remember June 4th, said Li Yiu-kee, a student and committee member of the Hong Kong Alliance in support of Patriotic Democratic Movements in China which organizes a mass candlelight vigil each year in a downtown park.

If Hong Kong students in trying to use democratic means to express their views on June 4th have these actions come under intimidation or threats, it's very important that the government protects this right, he told Reuters.

(Reporting by James Pomfret; Editing by Nick Macfie and Jeremy Laurence)

China