Two human rights groups expressed concern on Sunday over the fate of Huang Qi, a Chinese activist who friends fear was detained for offering support to families of children who died in the Sichuan earthquake.

Huang, who lives in Chengdu, capital of the southwestern province of Sichuan, which was devastated by the quake that killed at least 69,000, runs a Web site critical of the ruling Communist Party’s restrictions on political rights.

“In the midst of a national disaster, Huang Qi acted as a concerned citizen,” Sharon Hom, executive director of New York-based Human Rights in China, said in a statement.

“He sought to understand the situation and traveled to the disaster areas on numerous occasions to provide aid to the disaster victims. In this critical time … the authorities should be welcoming the mobilization of the whole society to act together to address the urgent needs of the victims,” Hom said.

The group said it had confirmed his detention on June 10 in Chengdu, but that police did not disclose the grounds. Huang was previously jailed on a charge of subversion of state power.

China has been seeking to present an image of unity and stability following the May 12 quake, but tensions have been rising among anguished parents who are demanding answers about the thousands of children killed when the disaster flattened schools.

PEN, which champions writers’ freedoms, expressed alarm over Huang’s detention and said two of his associates, Huang Xiaomin and Zhang Qi, were detained on May 16 after declaring their intention to join the rescue efforts.

Huang Xiaomin was released after 15 days but Zhang was still being held, the group said.

In a separate case, PEN reported that Zeng Hongling, a 53-year-old retired worker from the quake-hit area of Mianyang, was detained on June 9 on suspicion of “illegally providing information overseas”.

Zeng, who published a series of articles entitled “The Accounts of My Personal Experiences During the Earthquake” on an overseas Web site, was being held at a detention centre in Mianyang, PEN said.