The body of Saudi journalist Jamal Khashoggi was dismembered after he was strangled upon entering the Saudi consulate in Istanbul early this month, the chief prosecutor's office in Istanbul said Wednesday.

This was carried out as part of a premeditated plan, according to a statement by the chief prosecutor's office.

The statement is the clearest yet from the Turkish authorities about the fate of the Washington Post journalist, whose remains have not yet been found.

"The victim's body was dismembered and destroyed following his death by suffocation," the statement said.

"In accordance with plans made in advance, the victim Jamal Khashoggi, was choked to death immediately after entering the Consulate General of Saudi Arabia in Istanbul on October 2, 2018."

Turkish President Recep Tayyip Erdogan on Friday demanded that Saudi Arabia reveal the location of Khashoggi's body and hand over 18 suspects.