A delegation from Saudi Arabia has arrived in Turkey as part of a joint investigation into the disappearance of prominent Saudi journalist Jamal Khashoggi, two Turkish sources said on Friday.

Khashoggi entered the Saudi consulate in Istanbul on October 2 to get documents for his forthcoming marriage.

Saudi officials say he left shortly afterwards but Turkish officials and his fiancee, who was waiting outside, said he never came out.

Turkish sources have told Reuters the initial assessment of the police was that Khashoggi, an outspoken critic of the Saudi government, was deliberately killed inside the consulate.

Riyadh has dismissed the allegations as baseless.

A Saudi delegation arrived in Turkey as part of an agreement between Ankara and Riyadh to investigate the case, two Turkish sources said.

They did not give details about who was included in the group.

"A delegation has arrived in Turkey as part of efforts to form a joint working group with Saudi Arabia," one of the sources said.

Turkey´s state-owned Anadolu news agency said the delegation would hold talks with Turkish officials over the weekend.

Erdogan has previously said that Turkey could not remain silent over Khashoggi´s disappearance and called on officials at the Saudi consulate in Istanbul to prove he had left the building.

On Tuesday, Turkey´s foreign ministry also said the Saudi consulate in Istanbul would be searched as part of the investigation.