Dissidents who helped spearhead the 1989 Tiananmen Square protests on Monday blasted China's one-party rule and called on the international community to pressure Beijing into embracing democracy.

Exiled former student activist Wang Dan and intellectual Wang Juntao marked the 25th anniversary of the deadly crackdown in Beijing by launching a new movement from the United States, roughly translated as "All people around the world surround the city".

They are pressing for greater human rights in China and seeking to break through what they called the "figurative Great Wall" that they say is preventing the world's most populous nation from achieving democracy.

"Our movement will continue until the communist one-party dictatorship ends," Wang Dan told activists and reporters at an event in the US Capitol, where Chinese dissidents joined congressional leaders last week in commemorating the anniversary with a moment of silence.

Wang said the movement is a symbolic one, with potential for street protests in cities worldwide aimed at highlighting alleged abuses committed by Beijing.

"We're trying to organize more people to put pressure on the Chinese government," he told AFP afterwards.

"We want Washington to pay more attention to human rights and the political issues of China. I understand they're beating around the bush, not wanting to face the political problems with the Chinese government, but I think this is short-sighted."

Washington routinely raises human rights concerns with Beijing, but with China's economy growing 30-fold since 1990, maintaining positive trade relations with Beijing has become paramount.

The dissidents also warned that a quarter-century later, the children of those responsible for the crackdown that left at least hundreds dead have since become China's ruling elite, suppressing dissent with similar effectiveness.

"Currently, the sons and daughters of the June 4 slaughterers and butchers have hijacked the national power, becoming the super-rich nobility of the country," said Wang Juntao, reading from a statement.

"Over the past 25 years the Chinese people once hoped that as the Chinese economy took off and its treasury became more full, that after the Olympics were held (in 2012), the Chinese communist regime would become more confident and tolerant, implementing a constitutional system," he added.

"However it didn't happen that way. The Chinese communists became even more oppressive and brutal than before."

Wang Juntao said that many citizens, forced into line by authorities, "gave up fighting against the Chinese autocratic regime. They sat by and did nothing, or even helped the rise of this tyrannical monster."

China detains Chinese-Australian artist: associates
Beijing (AFP) June 02, 2014 - A Chinese-Australian artist has been detained in Beijing just before the Tiananmen Square anniversary, associates said Monday, with Canberra informing Beijing of its "strong interest" in the case.

Guo Jian, a former Tiananmen Square protester, was taken away on Sunday night from his home in Songzhuang, an art colony on the eastern fringe of Beijing, according to two of his acquaintances.

"My friend, the painter Guo Jian, has been taken away by the police," author Murong Xuecun wrote Monday in a posting on Sina Weibo, a Chinese version of Twitter.

Curator and critic Yang Wei, who is based in the same Beijing district as Guo, wrote in a Weibo message that Guo's detention was triggered by his recent work on a Tiananmen-themed art installation.

The 52-year-old Chinese-born Australian "was taken away by police from his Songzhuang studio today because he made a 'Meat Square' installation", Yang wrote in a late Sunday message, adding that the exhibition has not yet opened to the public.

Guo managed to send two short text messages to friends to say he had been taken by police, according to a Sydney Morning Herald report.

It cited a friend, artist Melanie Wang, as saying she was able to reach Guo on the phone briefly. He said police told him he would be released in 15 days.

Australia's Department of Foreign Affairs said it was troubled by the report.

"The Australian embassy in Beijing has contacted Chinese authorities to seek further information on the reported detention of Mr Guo Jian and to underline our strong interest in the matter," a spokesman told AFP.

"The Australian government stands ready to extend all possible consular assistance to Mr Guo."

Guo's detention came just days before the 25th anniversary of the June 4 military crackdown on pro-democracy protesters in Tiananmen Square, during which hundreds of people were killed -- by some estimates, more than 1,000.

China censors any mention of the crackdown and has ramped up already strict controls ahead of the anniversary.

Police have detained some 20 prominent liberal academics, lawyers and activists in recent weeks, according to the US-based group Human Rights in China.

Among them are Pu Zhiqiang, one of China's most celebrated human rights lawyers, and Gao Yu, a veteran reporter previously jailed for her writing on the Tiananmen protests.

Friends of Guo believe he was taken in by authorities because of a recent interview with the Financial Times, the Herald reported.

During the interview, he revealed he had created an artwork to privately commemorate the anniversary, covering a large diorama of Tiananmen Square with 160 kilograms of minced meat.

Guo reportedly emigrated to Australia in 1992 and returned to China in 2005.