"The suspected leader of Daesh, codename Abu Hussein al-Qurashi, has been neutralized in an operation carried out Saturday by the MIT in Syria," he announced on television, according to France 24.
Erdogan's remarks come as he is struggling to increase his chances of winning ahead of the decisive elections in Turkey.
An AFP correspondent in northern Syria said Turkish intelligence agents and local military police, backed by Turkey had on Saturday sealed off a zone in Jindires, in the northwest region of Afrine.
Residents told AFP that an operation had targeted an abandoned farm that was being used as a religious school.