BEIJING – An online campaign has urged people in 13 Chinese cities to rally every Sunday to press for government transparency and free expression, following a call last week for Middle East-style protests.

The new call, posted this week on a blog run by overseas-based human rights website, appeared to be from the same group behind a mysterious web campaign for protests last Sunday that echoed those rocking the Arab world.

The earlier call sparked a heavy police turnout at designated protest sites in Beijing and other cities. The events appeared lightly attended, however, and free of major incidents.

"What we need to do now is to put pressure on the Chinese ruling (Communist) party," said the renewed appeal.

"If the party does not conscientiously fight corruption and accept the supervision of the people, then will it please exit the stage of history."

Apparently attempting to make a statement without falling foul of China's security forces, participants were urged not to take overt action but to merely show up for the 2:00 pm "strolling" protests.

"We invite every participant to stroll, watch, or even just pretend to pass by. As long as you are present, the authoritarian government will be shaking with fear," it said.

China's government has indicated growing unease over the unrest in the Arab world, heavily censoring or blocking media reports and online discussion of the upheaval, which has toppled presidents in Tunisia and Egypt.

The call for weekly "Jasmine rallies" -- a reference to Tunisia's "Jasmine Revolution" -- was labelled as an "open letter" to China's rubber-stamp parliament. The National People's Congress opens its annual session on March 5.

The online appeal appeared to set the stage for a protracted but low-pressure bid to push the Chinese Communist Party for change, using the heavily policed Internet and word-of-mouth.

The letter echoed a number of the Arab grievances, including anger over government corruption, lack of transparency and official accountability, and the stifling of freedom of expression.

"If the government is not sincere about solving the problems, but only wants to censor the Internet and block information to suppress the protests, the protests will only get stronger," it said.

Police turned out in force at the gathering site in central Beijing on Sunday, but there were no overt demonstrations.

At least two people were seen being taken away by police, one for cursing at authorities and another who shouted: "I want food to eat!"

US Ambassador Jon Huntsman was spotted in the area on Sunday, but embassy spokesman Richard Buangan told AFP he was on a "family outing" and his presence was "purely coincidental".

No mention of the new protest call could immediately be seen on China-based websites or blogs.

Other cities included in the new call range from Harbin in the far northeast to Guangzhou in the south.

Authorities have detained two people, including Sichuan democracy activist Chen Wei, for spreading the earlier protest appeal on the Internet, the Hong Kong-based Information Center for Human Rights and Democracy said.

They face possible subversion charges, it said.

A woman in Harbin was detained on similar grounds after publicly denouncing "Communist Party corruption" on Sunday in a speech in front of the city government headquarters, it said.

Human rights campaigners say police have taken away at least 100 activists or rights lawyers amid official unease at the Middle East problems and as authorities tighten security for the parliament session.

US-based Human Rights Watch on Tuesday criticised the crackdown and in particular the disappearance of three Beijing-based rights lawyers -- Teng Biao, Tang Jitian, and Jiang Tianyong.

"The authorities have failed to give any reason or formal notification to their relatives, and all three are believed to be at risk of ill-treatment and torture," it said.