Authorities in the Chinese capital have detained a number of petitioners and are holding political activists under close surveillance to stop them holding public memorials for people considered politically sensitive during a traditional grave-sweeping festival.
"It is much stricter this year than in previous years," said Zhang Xianling, a member of the Tiananmen Mothers group for the families of victims of the 1989 Tiananmen Square military crackdown.
"This year, they're not just following us around but they insist that wherever we go, we travel in their vehicle," she said, adding that her family had been accompanied by state security police to Beijing's Babaoshan crematorium to sweep the grave of her son who died in the crackdown.
"They wouldn't let me walk there myself, because they were afraid that there would be journalists," Zhang said in an interview on Tuesday. "They had officers posted inside the crematorium, updating them."
"They told me not to go to Tiananmen Square to hold a demonstration, meeting or a protest," she said.
Police were also concerned that there should be no public memorials for late ousted premier Zhao Ziyang, a reform-minded liberal whose political fall came as then supreme leader Deng Xiaoping decided to send in the troops to clear weeks-long student protests, activists said.
"[The state security police] came to have a talk with me," said former protester Qi Zhiyong, who was crippled by a tank during the protests. "They told me not to go to Zhao Ziyang's family home on Qingming," he added, referring to the grave-sweeping festival which begins on Thursday in which the living tend graves and honor the dead.
"They told me not to go to Tiananmen Square, either," Qi said, adding that fellow Tiananmen protest veterans Li Hai, Zha Jianguo, and Gao Hongming had received similar warnings this week.
But she said the family would try to go to lay wreaths at the Square anyway.
"Tiananmen has a special meaning for us. A lot of martyrs laid down their lives there to advance the cause of democracy and human rights in China," Zhang said.
Meanwhile, a group of petitioners from the central Chinese city of Wuhan said they were detained by police after they tried to visit Babaoshan on Tuesday.
"We tried to go there to sweep graves," said petitioner Zhang Nengfang.
"They wouldn't let us in, and after that, they took us to Jiujingzhuang," she said, referring to an unofficial detention center on the outskirts of the Chinese capital.
"There were 11 of us there from Wuhan, but there were other people there as well, from Shanghai, Henan, every province," she added.
Shanghai-based petitioner Jin Yuehua said that an estimated 500-600 petitioners from Shanghai were in the Jiujingzhuang "black jail" facility, packed into the courtyard in the open air, with nowhere to sleep, or even sit down.
"There were more than 2,000 petitioners in there from all over China," Jin said. "We held a protest by the main gate, and then we broke the metal gates and everybody charged outside."
After that, Jin said a fleet of buses took the petitioners back to the Beijing southern railway station. "They were afraid we would stage a protest outside the gates of Jiujingzhuang," she said.
Reported by Grace Kei Lai-see for RFA's Cantonese service and by Jiang Pei for the Mandarin service. Translated and written in English by Luisetta Mudie.