The world’s first museum dedicated to the Tiananmen Square crackdown has opened in Hong Kong with an emotive ceremony and protests from pro-China demonstrators.

Almost 25 years after Chinese authorities’ brutal repression of pro-democracy protesters in Beijing, the permanent exhibition is one of the only places in China where the massacre of June 3-4, 1989, can be commemorated.

All reference to the crackdown is banned on the mainland, where many remain unaware of it.

“The one thing I remember most vividly was that 25 years ago, right after the massacre, Beijing residents told us one thing – that we must tell the true story of what happened to the world,” said Lee Cheuk-yan, chairman of the pro-democracy group which is funding the museum, on Saturday.

The Alliance in Support of Patriotic Democratic Movements of China also organises the annual June 4 candlelight vigil in Hong Kong attended by tens of thousands.

Lee dedicated the museum to those who sacrificed their lives for democracy.

The opening was disrupted by more than a dozen pro-China placard-wielding protesters who shouted at organisers outside the building, calling them “traitors”.

“They don’t talk about the Nanjing Massacre and only talk about June 4,” one shouted, referring to an incident in which China says more than 300,000 people were slaughtered by Japanese troops during World War II.

The demonstrators, who called themselves the 6.4 Truth group, said the Alliance presented a skewed account of the crackdown and that Chinese troops were also killed during the incident.

However, they did not deter a steady stream of visitors, including people from mainland China, to the museum.

“I feel after seeing this, (the view on the incident) will be completely different,” Kitty Kau, originally from the mainland and who has been living in Hong Kong for the past 12 years, told reporters.

“There are many people in China that don’t know about June 4. Even if they knew about it, they would not talk about it,” Kau said.

The 75 square-metre venue, in the commercial district of East Tsim Sha Tsui, features video clips and photographs – including the famous ‘Tank Man’ image of a civilian staring down a long row of military vehicles.