Crowds of media gathered as Mehmet Ali Agca was whisked under heavy guard from an Ankara prison to a military hospital where he was to be assessed for conscription into the armed services as required by law, The New York Times reported.
The newspaper said Agca, 52, looked tense in published photos.
The Daily Telegraph said a statement released by Agca's lawyer on his behalf was signed "The Christ eternal" and read: "I proclaim the end of the world. All the world will be destroyed in this century. Every human being will die in this century."
Agca shot the pope on May 13, 1981, in Rome's St. Peter's Square, wounding him in the stomach, left hand and right arm. He served 19 years in an Italian jail and then was transferred to Turkey where he served 10 years for the earlier murder of a newspaper editor.
Questions about Acga's motives for the shooting and mental health have remained over the years.
Theater accidentally screens 'Nymphomaniac' trailer instead of Disney's 'Frozen'
Texas principal bans speaking Spanish, stirs controversy