An explosive story about the massive wealth accumulated by the family of Prime Minister Wen Jiabao prompted the Chinese government to block the Web site of the New York Times early Friday morning, just days before a sensitive, once-in-a-
decade transition of power from Wen and others to a new generation of leaders.

The article says that assets controlled by Wen’s family are worth at least $2.7 billion, a shocking figure even in a country where government corruption is rampant and popular resentment against the elite has increased in recent years. The scandal also complicates the apparent intention of Chinese leaders to tackle corruption as a main issue at the Nov. 8 party congress, a move they have been signaling in the wake of other scandals that have dramatically shaken the party’s core leadership.

This month, the party took the rare step of accusing another prominent leader, Bo Xilai, of alleged massive corruption and wealth, but only as it began the process of purging him. He had a central role in China’s biggest political scandal in the past two decades, which involved the murder of a British businessman.

On Friday morning, China formally expelled Bo from the country’s top legislature, the National People’s Congress, where he was a deputy.

Wen is an especially vulnerable figure to charges of corruption because he has carefully cultivated an image as a benevolent figure who is trying to push the system toward greater reform. The wealth of Wen’s family, especially of his son and wife, has long been the subject of rumors. His wife was known among political watchers and reform activists for her involvement in the diamond industry. But the family’s holdings had not previously been documented in such detail.

China’s foreign ministry called the article a “smear” on China’s name that has “ulterior motives.” At a daily briefing, foreign ministry ministry spokesman Hong Lei said the government’s censorship of the story online was “in accordance with laws and rules.” But he did not deny the report’s contents.

In recent years, the slowing economy in China and a growing rich-poor gap, which has stalled many families’ efforts to climb into the middle class, has exacerbated public resentment of officials who are often able to operate on an entirely different level in business because of their connections.

In June, Bloomberg News reported that the extended family of Vice President Xi Jinping, who is poised to take over as president, had amassed $376 million. Government officials, apparently spooked, took the unusual step of not just censoring online discussion of the story but shutting down Chinese access to the Bloomberg site entirely.

The blocking of the New York Times Web site sets back an effort by the company to attract Chinese readers and advertising. This summer, it launched a new Chinese-language Web site, which had the potential of drawing especially on China’s booming luxury industry for revenue. According to Nieman Journalism Lab, the Times made a hefty investment in launching the Chinese edition, hiring hired 30 to 35 new journalists, translators and technologists.

The Times story on Wen was first posted on the English-language site Friday morning, then translated and posted on the Chinese site after a short delay. But by then, censors had blocked both Web sites completely.

“We hope that full access is restored shortly, and we will ask the Chinese authorities to ensure that our readers in China can continue to enjoy New York Times journalism,” Times spokeswoman Eileen Murphy said. “China is an increasingly open society, with increasingly sophisticated media, and the response to our [Chinese] site suggests that The Times can play an important role in the government’s efforts to raise the quality of journalism available to the Chinese people.”

“We will continue to report and translate stories, applying the same journalistic standards that are upheld across The New York Times,” Murphy added.

Chinese news Web sites run by independent foreign media have been complicated ventures, because of the risk that reports deemed controversial will be censored. By Friday noon in China, internet searches for the words “New York Times” in Chinese had been blocked. A Chinese-language microblog operated by the Times had been taken down. Viewers also reported a temporary blackout on BBC TV when it aired a news report about the Times story.

The Times took the unusual step of making available a downloadable Chinese PDF version of the story on its Web site, which would be easier to circulate by email in the face of censorship.

Max Fisher and Zhang Jie contributed to this report.