BEIJING — The Chinese authorities have refused permission for Liu Xiaobo, a Nobel Peace laureate paroled from prison for cancer treatment, to go abroad for care, one of his lawyers said on Thursday.

The authorities did not explain the rejection, according to the lawyer, Shang Baojun. The news undermined hopes among supporters of Mr. Liu, a writer and dissident, that he might be freed altogether, if not allowed to leave China. He remains under police guard in a hospital.

There have been signs that China’s leaders were growing sensitive to the international attention that Mr. Liu’s case has received, especially allegations that the government had effectively caused him to become gravely ill by failing to treat his liver cancer while he was incarcerated.

The judicial department of the northeastern province of Liaoning, where Mr. Liu has been serving his sentence and is being treated, released a statement Wednesday evening saying that he had received regular checkups in prison and that the cancer had been detected only a month ago.