BEIJING — A prominent Chinese writer living in Berlin said Wednesday that he had received a message from Liu Xiaobo, the Nobel Peace Prize winner who has been held by the Chinese authorities since 2008 and is serving a long prison sentence.

The writer, Liao Yiwu, who has known Mr. Liu for decades, declined to elaborate on how he received the message or what form it arrived in.

The message said: “I am O.K. Here in prison, I have continually been able to read and think. In my studies, I have become even more convinced I have no personal enemies. The nimbus around me is shiny enough by now. I hope the world could pay more attention to other victims who are not well known, or not known at all!”