HONG KONG — China has failed to improve its human rights record in the run-up to next month’s Olympics, with the government intensifying its crackdown on activists in recent years, Amnesty International charged in a report released today.

The report, which accused Chinese authorities of “tarnishing the legacy of the games,” came as the International Olympic Committee clarified that many Web sites will be blocked under controls applied by the communist government.

The clarification followed months of promises to journalists that China would allow unfettered access to the Internet during the Olympics, which begin August 8.

Amnesty said that the games, touted by Chinese and Olympic officials alike as a way to help expand freedoms in the authoritarian country, have instead led the government to muzzle critics in hopes of presenting an image of harmony and stability to the outside world.

“By continuing to persecute and punish those who speak out for human rights, the Chinese authorities have lost sight of the promises they made when they were granted the games seven years ago,” a deputy director in Asia for the London-based group, Roseann Rife, said. “The Chinese authorities are tarnishing the legacy of the games.”

Amnesty said that in the last year alone, thousands of petitioners, reformists, and others were arrested as part of a government campaign to “clean up” Beijing before the games. It said many of those arrested have been sentenced to manual labor without trial.

Amnesty also accused the International Olympic Committee of showing a “reluctance” to pressure China publicly on its human rights record.

Messages left with an IOC spokeswoman, Giselle Davies, asking for comment on the Amnesty report were not immediately returned.

The head of the IOC panel coordinating the Beijing Games, Hein Verbruggen, said last month that despite outside criticism of China’s record on human rights and other policies, the Olympics will be a “force for good.”

“I am absolutely convinced that bringing the games to China is way better than not taking the games to China,” he said.

A Foreign Ministry spokesman, Liu Jianchao, rejected today’s report, saying that people “who know China will not agree with this report.”

“We hope Amnesty can take off the tinted glasses it has worn for many years and see China in an objective way,” he said during a regularly scheduled news conference.

In one recent shift, the government announced it was setting up special protest zones during the games.

The designated protest areas will be in parts of three public parks, none of them closer than several miles from the main Olympic stadium. Human rights campaigners have assailed the protest zones as cosmetic, with one likening them to a “fishbowl” — sealed off from society at large.

While protests have become common throughout China — from workers upset about factory layoffs to farmers angry about land confiscation — the communist leadership remains wary about large demonstrations, fearing they could snowball into widespread anti-government movements.

After foreign groups critical of China’s human rights, press controls, and foreign policies in places like Sudan’s Darfur area began targeting the Olympics a year ago, Beijing ramped up an intelligence-collection effort to identify critics to keep them out. The melee of protests that greeted Beijing’s international torch relay in April brought a redoubling of efforts.