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.

Mr 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".

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.

Mr 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".