Turkey's state-run news agency says prosecutors have launched an investigation into a French former diplomat and analyst over accusations that he allegedly called for the assassination of President Recep Tayyip Erdogan.

The Anadolu Agency said Monday the move came after Erdogan's lawyer filed a formal complaint against Philippe Moreau Defarges, who said the only options left for Turkey were either a civil war or Erdogan's assassination. He made the comments on French television while speaking about the results of Turkey's April 16 referendum that will grant Erdogan greater powers.

Anadolu said Erdogan's lawyers accused Defarges of "incitement to the president's assassination."

Defarges, a senior fellow at the French Institute of International Relations, has apologized through Twitter, saying some of his words were "clumsy" and "misinterpreted."