"Despite our well-intentioned efforts to reveal the truth, no concrete results have come out of those meetings".
The 59-year-old's body "was dismembered and destroyed following his death", according to a report from Irfan Fidan's office.
The country is also asking Saudi Arabia to help locate Khashoggi's body, which still has not been found. Erdogan said Riyadh must disclose the identity of an alleged local collaborator said to have been involved in disposing Khashoggi's body.
In a written response, Mr Mojeb invited Mr Fidan to Saudi Arabia to question the suspects and determine "the fate of the body" and establish whether the killing was premeditated, the Turkish prosecutor's statement said.
He also held a second meeting with Fidan and visited the Saudi consulate in Istanbul.
The Saudi Crown Prince has been blamed for the killing of Jamal Khashoggi.
Turkey wants the suspects to be extradited.
He was "choked immediately" after entering Saudi Arabia's consulate in Istanbul to get documents for his forthcoming marriage, it said.More news: Heidi Klum Is Unrecognizable As Princess Fiona From ‘Shrek’
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A well-known critic of the Saudi authorities, the journalist Jamal Khashoggi went missing on 2 October.
Speaking in an interview with The Brian Kilmeade Show via teleconference, Pompeo said that the murder of Jamal Khashoggi in the consulate in Turkey violated "the norms of worldwide law", reports Xinhua news agency.
The case has brought near unprecedented worldwide scrutiny on Saudi Arabia and its powerful Crown Prince Mohammad bin Salman, whom Khashoggi had criticised.
"It seems the Saudi prosecutor is trying to obtain the information in the hands of Turkey rather than share the information he has", Selvi wrote Wednesday.
Mr Khashoggi, a Saudi national working for the USA press, was a well-known critic of his home country's rulers.
The editorial also urged the US Congress to impose sanctions on those responsible - "including, if the available evidence points to him, Mohammed bin Salman - and reshape US relations with Saudi Arabia". Khashoggi was murdered by Saudi officials, who claim the writer died as a result of an "altercation".
And in his first public comments since 2 October, the crown prince addressed the investment summit in Riyadh, denouncing Khashoggi's murder and vowing "justice will prevail".
(AP) Donald Trump said Khashoggi's death was the worst cover up in history.
As a Saudi dissident, Khashoggi was concerned he might be arrested for his work.