Updated

China's imprisoned Nobel Peace Prize laureate Liu Xiaobo's two brothers are being allowed to travel to a northeastern city to visit him in a hospital as concerns mount over his deteriorating health.

A German cancer specialist has arrived in China to help treat Liu — though it's not immediately clear if he had been able to see the dissident suffering from late-stage liver cancer. The specialist was allowed in by China following international criticism of Beijing's handling of Liu's illness and calls for him to be treated abroad.

The German foreign ministry says it has learned that Liu's health is deteriorating rapidly. Chinese doctors in charge of Liu's treatment said Friday they have stopped using cancer-fighting drugs so as not to overwhelm his severely weakened liver.