Chinese police have detained dozens of dissidents and human rights activists to stop them from staging protests or trying to meet Barack Obama, the US president, who has requested personal meetings with at least one prominent human rights lawyer during his three-day visit to China.

Mo Shaoping, one of China's best-known human rights lawyers, told the Financial Times he had been contacted by people “from the American side” to see whether he would meet Mr Obama, who arrived in China last night for the third leg of his ­inaugural Asia tour as ­president.

Mr Mo was subsequently questioned by Chinese public security officers who wanted to know details of the planned meeting. The US embassy said it had no knowledge of such a meeting.

Chinese police have detained dozens of dissidents and political reform advocates in recent days to stop them from protesting or trying to meet Mr Obama, say family members and human rights activists.

The crackdown comes as human rights groups worry that Mr Obama will play down China's poor human rights record in order to elicit co-operation from Beijing on issues such as climate change, trade and the economy. Sharon Hom, the executive director of Human Rights in China, said Mr Obama “should not give China a free pass on human rights”.

“One-quarter of humanity – as well as the rest of the international community – deserves better,” she added.

The FT has independently confirmed the cases of four Chinese activists who have been detained over the past two days, in advance of Mr Obama's visit.

They include Yao Lifa, a primary school teacher and democracy campaigner who was abducted by security officers on Saturday while walking with his baby daughter in his home town of Qianjiang, in Hubei ­province.

Mr Yao was able to contact his family briefly yesterday and inform them he has been moved to the neighbouring province of Hunan, apparently to prevent any opportunity for a meeting with the US president.

“All these people are being arrested because of Obama's visit, so there is no way he can come here and make deals with a dictatorship and pretend that China's human rights situation has nothing to do with him,” said Ai Weiwei, a prominent Chinese artist and social commentator.

“Obama can't just give us a showcase ‘town hall meeting' in Shanghai [an event which takes place today], he has to do something real and help those people who have been arrested because of him.”

The FT was able to confirm the house arrest of Zeng Jinyan, wife of the imprisoned human rights activist Hu Jia, as well as the detentions of Qi Zhiyong, a veteran activist who lost a leg during the suppression of student protests near Tiananmen Square in 1989, and Zhao Lianhai, organiser of an online support group for parents whose children were poisoned last year by melamine-tainted milk.