Beijing  - China sentenced a legal activist to three years in prison on Monday after convicting him of "illegal possession of state secrets," a charge apparently linked to his reports of protests by parents of children killed during last year's Sichuan earthquake.

A court in Chengdu, the Sichuan provincial capital, found Huang Qi guilty of illegal possession of unspecified government documents, the Chinese Human Rights Defenders (CHRD) reported.

CHRD said the charges were also believed to be linked to Huang's reporting of protests by parents who alleged that poor construction was responsible for the deaths of their children in school buildings destroyed by the earthquake.

Huang, who ran a popular website, had also given interviews about the protests to foreign journalists following the devastating earthquake, which killed more than 80,000 people.

He planned to appeal the sentence, CHRD quoted his wife, Zeng Li, as saying.

Zeng said the judge issued no written verdict on Monday and did not specify what state secrets Huang was guilty of possessing.

CHRD urged the central government to release Huang immediately, saying he was "punished simply for peacefully exercising his right to freedom of expression."

It said Huang suffered from several untreated health problems and had been denied visits from his family.

He was previously sentenced to five years in prison for "inciting subversion of state power" in 2003, but he was released early in 2005.

A court verdict is pending for another Chengdu-based activist, Tan Zuoren, who was tried in August after he independently investigated the deaths at schools in the Sichuan earthquake.

Ai Weiwei, a leading Chinese artist and architect, underwent surgery in Germany for a cerebral haemorrhage that he said was caused when he was beaten by police in Chengdu, after he had travelled to the city to support Tan during his trial. (dpa)