Image caption Chen Guangcheng caused a diplomatic incident when he broke house arrest in April

Chinese activist Chen Guangcheng has said he is just waiting for his passport to be issued, and intends to leave the country to study in the US.

He caused a diplomatic incident last month when he escaped house arrest and sought refuge in the US embassy.

Mr Chen says he has an offer to study at New York University, and all of the US formalities have been completed.

Meanwhile, he has challenged China's government to prove they did not order him to be kept under house arrest.

Mr Chen and his family had been illegally detained in their home in Shandong for almost two years before his escape.

He had previously served a four-year prison sentence after he exposed forced sterilisations and abortions carried out under China's population control policy.

The central government has blamed regional officials for his detention, but Mr Chen says he wants them to prove that assertion and punish those responsible.

"If they did not investigate then everyone will believe that they ordered it," Mr Chen told the AFP news agency.

"The central government needs to prove they were not behind my treatment in Shandong."

Mr Chen is still being treated in hospital for a leg injury he sustained during his escape.