Performers perform after the announcement of the Beijing Olympic Torch Relay route in Beijing in April. ((TEH ENG KOON/AFP/Getty Images))

Rights groups ramped up pressure Tuesday on China's government to improve civil liberties and press freedoms — pledges Beijing promised to fulfil in its winning bid to host next year's Olympics.

The human rights group Amnesty International said in a new report that Chinese authorities have violated those promises by heightening abuse and surveillance of political and religious dissidents, jailing journalists and closing publications focusing on social development.

With just one year before the Games, time is "running out for the Chinese government to fulfil its promise of promoting human rights as part of the Olympics legacy," Amnesty's secretary general Irene Khan said in a statement.

"Unless the Chinese authorities take urgent measures to stop human rights violations over the coming year, they risk tarnishing the image of China and the legacy of the Beijing Olympics."

The Committee to Protect Journalists, meanwhile, said that when the International Olympic Committee awarded the 2008 Olympics to Beijing seven years ago, China had promised to ensure that reporters could report freely in the country.

Under a regulation announced last year, foreign reporters can travel and conduct interviews in China without asking for government approval from Jan. 1 until mid-October 2008. The temporary freedoms do not extend to local Chinese journalists.

The group called on the government to free 29 journalists currently jailed in China and to loosen restrictions on local reporters. It also called on the IOC to pressure China more aggressively on press freedom issues.

Amnesty's report comes on the heels of one issued last week by Human Rights Watch, which also said the Chinese government has failed to live up to promises of greater human rights. It said Beijing has instead been clamping down on domestic activists and journalists.

Amnesty's release came as six activists were detained Tuesday after scaling down a part of the Great Wall with a large banner that read "One World, One Dream, Free Tibet 2008," the London-based Free Tibet Campaign and Students for a Free Tibet said in an e-mail statement.

Activists say China is using the Olympics to underscore its claims on Tibet. China says it has ruled Tibet for centuries, but many Tibetans say their homeland was essentially an independent state for most of that time. Chinese Communist troops occupied Tibet in 1951, and Beijing continues to rule the region with a heavy hand.

On Monday, police detained journalists at a rare protest in Beijing staged by a free-press advocacy group that accused the Chinese government of failing to meet pledges for greater media freedom.

The detentions, which came during a visit to Beijing by IOC President Jacques Rogge, followed the unfurling of posters depicting the Olympic rings made from handcuffs by members of Reporters Without Borders on a pedestrian bridge outside the headquarters of the Beijing Olympics planning committee.

In bidding for the games back in 2001, Chinese leaders promised IOC members that the Olympics would lead to an improved climate for human rights and media freedom.