Beijing  - A group of victims' relatives on Friday urged the government to investigate the deaths of hundreds of people during China's 1989 military crackdown on democracy protesters in Beijing's Tiananmen Square.

The Tiananmen Mothers group wrote an open letter renewing its demand for an official investigation into the military action on June 3-4, 1989, and a public announcement of the death toll and the names of the dead.

The group addressed its letter to members of the annual National People's Congress, the nominal parliament of China's ruling Communist Party, which is scheduled to open next week.

It also urged compensation for relatives of those who died in 1989 and punishment for those held responsible for "a massacre against peaceful demonstrators and civilians."

"Over this long stretch of time, government authorities deliberately played down June Fourth, forbade discussion among our people of June Fourth and prohibited the media from touching on June Fourth," said the letter, which was circulated by the New York-based Human Rights in China group.

"China has become like an airtight 'iron chamber,'" said the group, which issued similar appeals to the National People's Congress last year and in 2006

The Tiananmen Mothers is an informal group of relatives and supporters of victims of the 1989 crackdown that has campaigned since 1995 for an inquiry into the crackdown and for the government to offer an apology and compensation to the families of victims.

It is led by retired professor Ding Zilin, whose 17-year-old son died in Tiananmen Square, and includes dozens of other parents and supporters of victims.

In 2006, the group said it had confirmed that at least 186 people died and more than 70 were injured in Beijing overnight on June 3-4, 1989, but estimated that this number was only a "small percentage" of the probable number of casualties. (dpa)