A Chinese man was sentenced to three years in prison on Monday for breaking China's “state secrets” laws after he tried to provide legal advice to parents whose children died in shoddily built schools in the Sichuan earthquake last year.

After 17 months of secretive criminal proceedings that human rights groups said fell far short of China's legal regulations and international human rights standards, Huang Qi, 46, a veteran rights activist, was sentenced in a court in Sichuan.

Zeng Li, Mr Huang's wife, told the Financial Times: “Huang Qi was only trying to help the parents of earthquake victims prove those schools were poorly built and he gave interviews to some foreign media, and just for that he was punished.”

The government has said 5,335 schoolchildren died in the earthquake or are missing.

The sentence came less than a week after Barack Obama visited China. Scores of dissidents and political activists were taken into custody by police to prevent them from trying to meet the US president or issue public statements on China's human rights situation.

Of 30 supporters who attempted to attend the “open” trial on Monday, only Ms Zeng and Mr Huang's mother were eventually allowed into the courtroom to witness the 10-minute verdict and sentencing procedure.

Mr Huang was abducted by plainclothes state police officers on June 10last year, less than a month after the earthquake and was tried in a closed trial on August 5 this year.

The verdict convicted Mr Huang of possessing “three documents issued by a certain city government”, according to Ms Zeng.

But the judge did not specify what kind of documents they were, which city government issued them or how their contents constituted state secrets, a vaguely defined charge that is often used in China to imprison critics of the government or Communist party.

Mr Huang appeared very thin with yellowish skin, according to Ms Zeng, who said he was barely even able to tell the court that he wished to appeal.

In a separate case, a student leader of China's 1989 pro-democracy movement who has lived in the US for years was put on trial in another Sichuan court on Thursday, a day after Mr Obama left China.

Zhou Yongjun, who holds a US green card, faces fraud charges in Sichuan that allegedly involve a bank in Hong Kong at which he tried to set up an account using a Malaysian passport, according to human rights groups.

China and Hong Kong operate under separate political and legal systems and human rights groups say the charges are a pretext to punish Mr Zhou for years of activism dating back to the 1989 student movement and the bloody army-led crackdown that ensued.

Mr Zhou, 42, has been in custody in Sichuan since he was arrested in September last year as he was trying to enter China from Hong Kong.