Authorities in the Chinese capital have boosted security ahead of the anniversary of a 1989 military crackdown on student-led pro-democracy protests in Beijing's Tiananmen Square.
Dissidents and rights activists said Beijing police have begun a fresh round of surveillance and summonses for questioning, known as "drinking tea," this week.
"Things have been pretty tense here the past couple of days," said a prominent Beijing-based activist who declined to be named. "Here in Beijing, the anniversary of June 4 is almost upon us."
He said he had received a phone call from police on Monday calling him for "a chat."
"There are a lot of plainclothes police ... out on the streets. Before it was just on Tiananmen Square, but now they have them at the intersections too, and they have even started extending out to the suburbs."
No form of public memorial has ever been held for those who died when the People’s Liberation Army cleared thousands of student-led pro-democracy protesters from the center of Beijing.
Instead, police regularly clamp down on any form of public protest or discontent at this time of year.
Ordinary Chinese who come to the capital to lodge complaints against officials back in their hometowns are frequently rounded up in buses and sent to unofficial detention centers or "black jails" ahead of politically sensitive dates.
A petitioner from the northeastern province of Jilin surnamed Liu said police had already moved to put a number of his fellow petitioners under surveillance or detention.
"There are a lot of people under surveillance back in their hometowns right now, because it's nearly June 4," Liu said. "I don't know the exact number, but they are being watched by the neighborhood committees, the local security patrols, and the police."
"They are watching the main family home of anyone who has tried to kick up a fuss of any kind in the past."
"These are people complaining through normal channels," he said.
The 1989 crackdown culminated in the use of Chinese military tanks and troops firing live ammunition on the streets of Beijing on the night of June 3 and the early hours of June 4.
Hundreds are thought to have died during the violence, which followed the ouster of reformist premier Zhao Ziyang by then supreme leader Deng Xiaoping, but no figures have ever been released.
Zhao spent nearly two decades under house arrest before his death on Jan. 17, 2005, which went unnoticed by many in China.
While his name is seldom spoken in political circles, Zhao's death has become a focal point for those who are increasingly disgruntled with the current government.
His posthumous memoir, titled in English Prisoner of the State: The Secret Journal of Zhao Ziyang, went on sale in 2009 to coincide with the 20th anniversary of the military crackdown—which Zhao opposed at the cost of his political career and personal freedom.
Groups like the Tiananmen Mothers have tried to compile lists of victims and the places that they died, as well as calling annually for an official reappraisal of the protests and the crackdown which ended them.
Some victims, like Changchun-based democracy activist He Zhenchun, were permanently crippled in the crackdown.
He, who served a five-year jail term in the wake of the 1989 protests for "counterrevolution," said he now has terminal lung cancer.
"The situation right now is that my health is very poor," said He, who sells handicraft items from a street stall to eke out a living for his family.
He said police had left him alone this year following his diagnosis last December.
"They don't come looking for me any more," he said. "I've got lung cancer now."
Beijing residents say this year's clampdown is particularly harsh, coming hard on the heels of dozens of arrests of dissidents and lawyers amid fears of a "Jasmine" revolution inspired by recent uprisings in the Middle East.
This year also marks the 90th anniversary of the founding of the ruling Chinese Communist Party on July 1, with the authorities ordering a slew of patriotic TV programs and public celebrations.
Reported by Qiao Long for RFA's Mandarin service. Translated and written in English by Luisetta Mudie.