A New York-based human rights group is urging people to mark the fifteenth anniversary of the Chinese government's crackdown on pro-democracy demonstrators in Beijing's Tiananmen Square. The group is displaying many previously unpublished photographs of the historic protests and their violent end.

The Human Rights in China group says it solicited people in China and abroad for photographs of the protests and it now has more than three thousand pictures. At least half of the photos have never been published before. Many belong to demonstration participants and their families.

Organizers say one hundred of the photographs will be exhibited in 27 cities in North America, Europe and Asia - including Hong Kong and Taipei. The group is compiling all of the photographs on a Chinese-language internet website.

Tang Baiqiao is chair of the China Peace human rights group, which helped organize the exhibition. He says the photographs are a powerful way of reminding people about the brutal crackdown. "It makes you have a very strong feeling about this, this massacre. So I think should publish the photographs every year, starting from this year," he says. "Maybe next year we can publish more, maybe make a book."

Organizers have also planned several other demonstrations in New York, including a candlelight vigil at the Chinese embassy.

The demonstrations mark the brutal crackdown that took place on June 4, 1989. Chinese government troops suppressed a pro-democracy protest in China's capital and killed hundreds, perhaps thousands, of unarmed demonstrators.

Organizers of this year's demonstrations say they want to remind young people of what happened that day.