The United States rebuked China yesterday over the arrest of a veteran dissident on Monday, but Beijing replied by calling on foreign countries not to interfere in domestic Chinese affairs.
The sharp exchange indicated that China has begun a tough new phase in its treatment of pro-democracy activists, who have been trying to register an opposition party since June.
The clear message is that Beijing has lost patience with the small but cohesive group of activists which has been trying to register an opposition party in different locations. Before now members were detained and released after a few days but these arrests are more serious, family members say.
The US State Department spokesman, Mr James Rubin, said: "We conveyed our strong views to officials in the Chinese Ministry of Foreign Affairs today in Beijing and urged the authorities to release Xu immediately. We view his detention for peacefully exercising fundamental freedoms guaranteed by international human rights instruments as a serious step in the wrong direction."
This was a pointed reference to the UN International Covenant on Civil and Political Rights which Beijing signed in October but has yet to ratify.
Some 191 Chinese dissidents appealed yesterday for the immediate release of Mr Xu and of two other senior members of the fledgling China Democratic Party, Mr Qin Yongmin and Mr Wang Youcai, detained in provincial cities on Monday, according to a Hong Kong human rights group.
Drawn from 22 provinces, the dissidents claimed in a letter that the arrests illustrated the authorities' "hypocrisy". China's human rights record has worsened, they said.
Mr Xu (55) announced the setting up of a Beijing branch of the unregistered China Democracy Party on November 9th. His wife, Ms He Xintong, a retired teacher, said yesterday: "They cannot shake Xu Wenli from his determination to be involved in the cause of democracy and human rights."
Two other members of the China Democratic Party were released and a third was detained, leaving nine still in police custody.
Two former Tiananmen Square student leaders began a 48-hour hunger strike yesterday to protest against the new round-up of dissidents.