China's human rights situation is getting worse, a senior US official said in Beijing on Friday, as reports of another detention increased fears of a crackdown on activists and lawyers.

Uzra Zeya, who led the US side in annual bilateral rights dialogue, cited increasing pressure on activists' friends and relatives and religious restrictions in Tibet and Xinjiang.

"I think we have continued to see a deterioration in the overall situation in China," said Zeva, the acting assistant secretary of state for democracy, human rights and labour.

"The specific issue of the targeting of family members is one reason for that assessment: the case of the family of Liu Xiaobo, of Chen Guangcheng and other instances. This is a worrisome trend and one we have raised at senior levels."

She added: "Looking at policies towards ethnic and religious minorities, the situation in the Tibetan Autonomous Region and [Xinjiang] Uighur Autonomous Region, particularly with respect to repressive measures relating to religious practice, we would also say that supports the same overall assessment."

The first round of the dialogue since China's power transition came amid growing concern about recent detentions. Human Rights Watch says that at least 16 activists from Beijing and Jiangxi province have been put under criminal detention for publicly calling on the government to require officials to disclose their assets, despite the country's leader, Xi Jinping, announcing a crackdown on corruption.

Zeya said the US had highlighted one of those cases – the detention of Xu Zhiyong, a well-known legal scholar and rights defender – as well as raising concerns about Liu Xiaobo, the jailed writer and Nobel peace prize winner; the author's wife, Liu Xia, who has been under house arrest since shortly after he won the award; and others.

Other cases raised by the US included those of the jailed Tibetan film-maker Dhondup Wangchen and the ethnic Mongolian activist Hada, who was released from jail in December 2010 but remains in detention. The Chinese responses "fell short of our expectations", Zeya added.

Reports of another detention by state security – this time of the veteran journalist Xiao Shu – emerged shortly after Zeya's comments. Xiao was among the friends and supporters who had called publicly for Xu Zhiyong's release. He reportedly refused a demand from state security to leave Beijing last month.

"Like Xu Zhiyong, he is very constructive and very moderate in his viewpoint. They place a lot of emphasis on practical objectives and frame it often within existing party language," said David Bandurski, who runs the China Media Project at Hong Kong University.

Bandurski noted what appeared to be broader attempts to control debate recently, such as reports of "seven don't speaks" – an edict to academics and others to avoid seven sensitive topics.

China publishes an annual report on the US human rights record in response to US criticisms.