SHANGHAI — Chinese officials have sharply criticized foreign reporters here over their coverage of the riots in Tibet, accusing them of biased reporting and preventing them from traveling to Tibet or neighboring provinces to report on the unrest.

The government has also begun a propaganda campaign aimed at persuading the public that the Dalai Lama, the exiled Tibetan leader, instigated the violence in Tibet on March 14 and that China was a victim of separatist terrorist activity.

The Tibetan government in exile said Tuesday that the death toll from the demonstrations was about 140. Previously, it had said that 99 protesters had died. China has put the death toll at 22.

The Chinese government’s effort is the clearest sign yet of its concern that the Tibet unrest, as well as antigovernment protests over Darfur, could disrupt the Olympic Games this summer in Beijing.

The government appears to be blocking foreign Web sites inside China and censoring foreign television broadcasts here about Tibet. Youtube.com was blocked after the riots began, and CNN and BBC broadcasts regularly go black after mention of riots in Tibet. The New York Times Web site appears to have been blocked or censored in recent days.

Over the weekend, the government allowed Chinese Web sites, which are usually heavily censored for political content, to post sharp critiques of foreign news media reports about Tibet and to show graphic, violent images of Tibetans looting and attacking ethnically Han Chinese in Lhasa, the Tibetan capital, on March 14.

The images have fueled outrage in China and led to a flurry of Web postings vehemently critical of Tibetans.

State-controlled news media have been allowed to report from Tibet and neighboring areas where violent protests occurred. But foreign journalists have been denied access to Tibet and blocked from reaching neighboring regions with large Tibetan populations. Many foreign reporters who managed to get into Tibet after the riots were forced to leave.

Foreign journalists in China say these actions violate the government’s pledge to give them greater press freedoms and access to the country in the months leading to the Olympics.

“At a time when China is promising to become more open with the world, this is a big disappointment,” said Jocelyn Ford, a freelance journalist based in Beijing and chairwoman of the media freedoms committee of the Foreign Correspondents Club there.

To appease foreign reporters, Beijing told several journalists Monday that a group of about 12 correspondents would be able to travel to Lhasa for a special government-guided tour of the city this week. Whether they will be allowed to interview people independently is unclear.

The government has issued no official statement criticizing the foreign news media. But in recent days state-controlled newspapers, television stations and Internet sites have been carrying stories and commentary with a common theme: foreign media distortions. The official Xinhua news agency released a story over the weekend suggesting that film shown by CNN misrepresented the situation. CNN, in a statement, said its coverage was accurate.

“I used to think the Western media were fair,” wrote one person who posted comments online, according to China Daily. “But how could they turn a blind eye to the killing and arson by rioters?”

Gao Zhikai, a former Ministry of Foreign Affairs official, said the foreign media were partly to blame and contended that many of the reports about Tibet had been biased. “If you read the foreign media, the only message you can get is that China is very heavy-handed, and they are doing a lot of bad things in Tibet, and they are totally out of their minds,” Mr. Gao said. “And they talk about the Dalai Lama as if he’s God.”

James Miles, a journalist with The Economist who happened to be in Lhasa during the riots, was praised on Chinese state television, though, after he reported in The Economist and gave an interview to CNN describing the riots and saying that Tibetans were singling out Han Chinese, burning their shops, throwing stones and assaulting them.

The point, some Chinese commentators said, was that the rioters were killing innocent Chinese rather than that the government was shooting protesters.

The government also repeats over and over that the riots were orchestrated by the “Dalai clique” to upstage the Olympics.

The Dalai Lama has said in the past week that he did not organize the riots and that he supports the decision to allow China to hold the Olympics.

The government also insists that the foreign news media do not understand Tibet or efforts by the government to bring prosperity to the region.

Journalists here say the travel and reporting restrictions are making things worse. “Reporters are not even allowed to see the whole story in Tibet,” said Ms. Ford with the Foreign Correspondents Club in Beijing. “We don’t even know why people rioted or what they wanted.”

Georg Blume, a reporter for the German newspaper Die Zeit, was one of the few Western journalists to get into Lhasa after the riots. He arrived on March 15, he said, and saw huge areas damaged by riots, fires and looting.

He says some Tibetans who took part in the riots said they were proud that they were finally able to stand up to the Chinese; others said they were ashamed of the violence.

They complained about social discrimination, unequal pay and rumors that almost everyone had heard that Tibetan monks had been arrested, and even killed, in the days before the riots.