Turkish President Recep Tayyip Erdogan on Monday called on Riyadh to prove its claim that the Saudi Arabian journalist Jamal Khashoggi, who has been missing since last week, left the Saudi consulate in Istanbul.

The disappearance of Khashoggi, previously a prominent newspaper editor in Saudi Arabia and an adviser to its former head of intelligence, has sparked global concern, particularly after Turkish sources said at the weekend that authorities believed he was killed inside the consulate.

Khashoggi left Saudi Arabia last year saying he feared retribution for his criticism of Saudi policy in the Yemen war and its crackdown on dissent.

On Tuesday he entered the consulate in Istanbul to get documents for his forthcoming marriage.

Saudi officials say he left shortly afterwards but his fiancee, who was waiting outside, said he never appeared.

"We have to get an outcome from this investigation as soon as possible. The consulate officials cannot save themselves by simply saying 'he has left'," Erdogan told a news conference in Budapest, where he is on an official visit.

Erdogan, who said he was personally following the case, added that Turkey had no documents or evidence at hand regarding the case.

A Saudi source at the consulate has denied that Khashoggi had been killed at the mission and said in a statement that the accusations were baseless.

The consulate has also denied that Khashoggi was abducted.

Khashoggi is a familiar face on political talk shows on Arab satellite television networks and used to advise Prince Turki al-Faisal, former Saudi intelligence chief and ambassador to the United States and Britain.

His disappearance is likely to further deepen divisions between Turkey and Saudi Arabia.

Turkey has asked for permission to search Saudi Arabia's consulate in Istanbul, broadcaster NTV said yesterday.

A Turkish official also said Saudi Arabia's envoy to Ankara had been summoned to the foreign ministry for a second time on Sunday."It has been conveyed to him that we expect full co-ordination in the investigation process," the official said.

The two Turkish sources told Reuters Turkish authorities believe Khashoggi was deliberately killed inside the consulate, a view echoed by one of Erdogan's advisers, Yasin Aktay, who is also a friend of the Saudi journalist.

Erdogan told reporters on Sunday that authorities were examining camera footage and airport records as part of their investigation.

Saudi Arabia's consul in Istanbul opened up his mission to Reuters on Saturday in an effort to show that Khashoggi was not on the premises.

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