Dozens of elderly parents in Beijing have gathered to mourn their children who were killed in the June 4 crackdown at Tiananmen Square, a local rights group says.

The meeting was held on Sunday at the Chaoyang district home of Zhang Xianling , who lost her 19-year-old son Wang Nan , according to a report released yesterday by the Hong Kong-based Information Centre for Human Rights and Democracy.

The centre said a couplet hanging in the sitting room where the service was held read: "Seeking truth is the basic right of Tiananmen mothers" and "Upholding justice is the hope in the deep darkness of the night".

Ms Zhang yesterday confirmed the ceremony had taken place and said that several days beforehand Ministry of State Security officers made her agree to several conditions.

"They wanted us to make sure no outsiders, particularly foreign journalists, took part in the mourning ceremony," she said. "Besides, they also warned us to stay inside. I agreed to their conditions and they said we could proceed with the gathering."

Up to 50 bereaved parents from 40 families attended the gathering, held once every five years. Most were in their 70s or 80s and some were wheelchair-bound. "We began observing silence and bowing in front of our children's photos at roughly 3pm," Ms Zhang said.

One absentee was Ding Zilin , founder of the Tiananmen Mothers organisation. "Ding Zilin was supposed to deliver a memorial speech, but police wouldn't let her leave home," Ms Zhang said.

She said all those present were incensed by the decision to prevent Ms Ding from mourning her son. She said Ms Ding's movements were being limited until the 20th anniversary had passed. Her phone rang unanswered several times yesterday.

Tan Shuqin , 70, who lost her daughter in the crackdown, made the memorial speech on behalf of all the parents. "Our courageous, intelligent, heroic and innocent sons and daughters, we have by no means forgotten you all although 20 years have passed," Ms Tan was quoted as saying by Ms Zhang.

"All Tiananmen mothers will resolve ourselves to [seeking justice] without hesitation and we do believe your grievances will be resolved some day. May you rest in peace, our beloved children."

Ms Zhang said the ceremony lasted slightly more than two hours before they parted ways at 5.10pm.