US Edition For the first time, major international websites devoted to human rights, such as those of Amnesty International and Human Rights Watch, were freely accessible on computer screens across the city.
English speakers were able to see and read articles with headlines such as "Chinese authorities' broken promises threaten Olympic legacy". The Amnesty site also showed Chinese prisoners apparently at a sentencing rally before being executed.
A block on the BBC Chinese language news site was also lifted, along with other foreign media whose sites previously triggered a message saying: "Internet Explorer cannot display the webpage" when accessed from inside China.
It was not clear whether the change in policy applied to all of China's 250 million internet users, now the largest number in the world, but there were reports that sites were also visible in other cities.
Despite the relaxation of censorship, President Hu Jintao, in a rare press conference with foreign journalists, seemed to issue a warning on how China expected the Games to be portrayed.
Saying he welcomed journalists to report on the Games, Mr Hu added: "Of course, we also hope that during their coverage foreign reporters will follow and abide by Chinese laws and regulations."
He pledged that political as well as economic reform would be strengthened after the Games, but he refused to give any ground to critics of China over its human rights record, refusing to answer one question on the subject.
"We believe that politicising the Olympics does not favour resolving these issues, and also violates the Olympic spirit," he said.
The change in the internet policy follows a bitter row between members of the International Olympic Committee, its president and staff, and the Beijing Olympics organising committee BOCOG this week.
Journalists complained to the head of the IOC's press commission, Kevan Gosper, that websites continued to be blocked in the Olympic village and media centre despite promises that reporters would be allowed the same freedom as at previous Games.
Mr Gosper accused IOC officials of having done a "secret deal" with Beijing to allow continued censorship, and suggested that the IOC president, Jacques Rogge, who had also previously promised unfettered access to journalists, must have known about it.
It is understood that following his allegations, the IOC reopened negotiations with Beijing, whose chief spokesman had acknowledged that some sites would remain censored.
The result is a compromise, since many sites ordinarily accessible elsewhere in the world, including those of Tibet campaign groups and of Falun Gong, the religious movement heavily persecuted in China, remain blocked.
"Following discussions the IOC held with BOCOG and Chinese authorities regarding difficulties experienced this week in accessing some web sites, the IOC is pleased to see that the issues are being quickly resolved," said Giselle Davies, the IOC's chief spokeswoman.
The move was also welcomed by Amnesty and other groups, who called for the lifting to be made permanent and to apply to other sites blocked because of political content.
But Sun Weide, the BOCOG spokesman, refused to confirm any change in policy. "Some sites are blocked under Chinese law, but I do not have further information on which," he said.