Some Web sites remained inaccessible to reporters as competition got under way on Saturday at the Beijing Olympics.
China's communist government routinely filters its citizens' access to the Internet, but in the runup to the Olympics Chinese officials and officials with the International Olympic Committee vowed there would be no censorship of the Internet for accredited journalists covering the games.
Some sites were unblocked 10 days ago after reporters arriving to cover the games found them blocked and complained to the IOC, but others remain inaccessible, including sites related to the Tiananmen Square protests, Tibet, Taiwan and the Dalai Lama.
While searches for these keywords turned up long lists of Web sites, attempts to open some of them resulted in a message saying the page could not be displayed.
A search for information about the outlawed Falun Gong spiritual movement not only drew that error message but froze the search engine and prohibited further searches for several minutes. Sites that host thousands of blogs appeared to be open, but specific blogs remained blocked.
A statement by Chinese officials indicated they had gone as far as they intend to go.
"Yes, we promised to provide free access to the Internet except for a few that would jeopardize our national security and would not be good for the healthy growth of our young people," said Wang Wei, executive vice president of BOCOG, the Olympic organizing committee.
"As in any other country, there are some kinds of limitations," Wang added. "However, I think we are going to provide sufficient access for the media to cover the games."
IOC spokeswoman Giselle Davies suggested reporters should keep pushing the Chinese.
"Sites that you need to have for your job, it's important that you raise them for BOCOG's awareness," Davies said. "It's ongoing work."
Rebecca MacKinnon, who studies Internet censorship in mainland China, said none of the changes have affected Chinese-language sites.
"The censorship situation for those Web sites has not loosened at all," said MacKinnon, who teaches journalism at the University of Hong Kong.