China has freed Zhang Jingsheng, a dissident sentenced to 13 years in jail in 1989.
His release had been delayed to avoid controversy during the June 4th anniversary of the Tiananmen Square massacre, a Hong Kong-based human rights group said yesterday.
The Information Centre for Human Rights and Democracy in China said the release might be linked to a US Senate vote expected next month on whether to grant China permanent normal trade relations (PNTR).
Mr Zhang was jailed in 1989 following the student-led pro-democracy movement and was released on Tuesday, the group said.
His sentence was cut by two years because of overtime on work done in prison, it said.
China had planned to grant the 46-year-old dissident parole on June 3rd or 4th but delayed his release as the anniversary of the bloodshed approached, Mr Frank Lu, founder of the Information Centre, said.
Mr Zhang was jailed for "counterrevolutionary" crimes after forming a labour movement and giving a public speech, the group's statement said.
He was also jailed for four years in 1981 for taking part in the 1978-1979 Democracy Wall movement.
The Hong Kong group said Mr Li Wangyang, a senior member of Mr Zhang's labour movement, was released on parole on June 8th.
PNTR has already won House of Representatives approval, and Senate passage is virtually assured whenever a vote is scheduled.
On Monday the Senate Republican Leader, Mr Trent Lott, said he would not "rush" to schedule a vote on the landmark China trade bill, despite calls by the White House and the business community for swift passage.
PNTR would end the annual US ritual of reviewing China's trade status.
It would permanently guarantee Chinese goods the same low-tariff access to US markets as products from nearly every other nation.
China would in turn open a wide range of markets from agriculture to telecommunications to US businesses under the terms of a trade agreement signed in November 1999 that would help Beijing enter the World Trade Organisation.