The change grants China's Web-using public access to the previously unviewable sites of the Washington Post, Los Angeles Times, San Francisco Chronicle and Boston Globe, which were blocked as recently as Sunday. It was unclear exactly what day the unblocking occurred.

Among those still blocked are the sites of CNN, Voice of America, Time Magazine and the Atlanta Journal-Constitution, as well as a slew of Western human rights groups including Amnesty International.

China unblocked The New York Times site in August. While the government has not stated why, the Times itself reported in passing in a story on proxy servers that the change happened as a result of the paper's top editors and reporters raising the issue during a July interview with Chinese President Jiang Zemin.

An official at the Ministry of Public Security, which oversees Internet control, refused to discuss why it blocks or unblocks any sites. Yet one key Chinese expert said the Sept. 11 terrorist attack on the United States may have provided the impetus.

“Opening such websites is a statement that the Chinese government wants to allow people to get true access to the information about this,” said Zhu Feng, director of the international security program at Peking University in Beijing. “It is a constructive action my government took at this critical time because they feel people have a right to know what is going on around the terror attacks.”

Western observers were skeptical, though, noting that most Chinese people can’t read English anyway.

“I wonder how many people really look for news in English on the Internet in China,” said Sophia Woodman, research director for the New York-based group Human Rights in China. “The point of opening these sites may not have anything to do with domestic expression so much as getting China better press internationally.”

Bureau chiefs for the affected sites were unaware of the change, most consumed in recent weeks by news of the Sept. 11 suicide hijacker attack on the US.

Despite the switch, it remains impossible on even the unblocked media sites to search terms such as Falun Gong, the banned spiritual movement targeted by the government here as a cult, or Taiwan, the breakaway province China insists is still a part of its territory. Additionally, searching such terms on portals like Yahoo! and Google yield errors either during the search or in attempts to access the sites that are found.

Yet critical articles about China are easy to locate on those websites if they are top news of the day or if other search words are entered. A search for "Jiang Zemin" on the San Francisco Chronicle's site, for example, found a biting satire by columnist Jon Carroll on Aug. 14 mocking the Chinese president's answers in that New York Times interview.

The US has taken an increasing interest in helping the Chinese people overcome the censors. California-based Safeweb Inc., which creates technology to circumvent such blocks, received $1 million from the CIA via a venture capital firm it uses to fund start-ups working with intelligence-related technology. And Congress last year allocated $800,000 for Voice of America's Internet-based news operations in an effort to boost VOA's ability to reach the Chinese people.

The Chinese censors are savvy, though, blocking proxy servers when necessary and keeping on top of new ways to get to blocked sites. Earlier this year, for instance, users could read CNN.com by going to Europe.CNN.com, but that was halted in February.

The continued blocking of the Atlanta paper may reflect the unevenness of the government’s site-blocking efforts. Even before the Times was unblocked, for example, Internet users could read much of the paper -- including stories on China -- through Yahoo’s New York Times section. And the International Herald Tribune, an overseas collaboration that chiefly reprints New York Times and Wa shington Post stories, was accessible.

Furthermore, a lot of syndicated content from the blocked sites, including anti-China commentaries, could be found on a host of other, never-blocked Western media sites. Among those outlets never blocked were the nation’s two largest dailies, USA Today and the Wall Street Journal, as well as the Chicago Tribune and ABCNews.Com. Reporters from those publications often joke that their goal, in fact, is to get blocked.

“In The New York Times case, it takes the top leaders to unblock it, which makes me wonder whether it’s a totally thought out censorship system,” said CNN’s Beijing bureau chief Jaime FlorCruz. “It has a very erratic nature. Sometimes I attribute that to an ad-hoc approach to censorship. It's almost a bungling erratic approach. There’s no rhyme or reason.”