Turkish President Recep Tayyip Erdogan on Monday asked Saudi officials to prove their claim that missing journalist and Riyadh critic Jamal Khashoggi left the Saudi consulate in Istanbul.

Erdogan's comments' came after media reports said his government sought permission from Saudi authorities to search the consulate premises in Istanbul.

Khashoggi, a Washington Post contributor, vanished last Tuesday after entering the consulate to receive official documents ahead of his marriage to a Turkish woman.

“Consulate officials cannot save themselves by saying that he left the building... Don't you have a camera?” Erdogan told a news conference in Budapest.

“If he left, you have to prove it with a footage. Those who ask Turkish authorities where he is should ask what happened.”

Police said at the weekend that around 15 Saudis, including officials, arrived in Istanbul on two flights on Tuesday and were at the consulate at the same time as Khashoggi.

A Turkish government source told AFP at the weekend that the police believe the journalist “was killed by a team especially sent to Istanbul and who left the same day”.

Riyadh vehemently denies the claim and says Khashoggi left the consulate.

Turkey on Monday sought permission to search the consulate premises, Turkish NTV broadcaster reported.

The move came after the foreign ministry summoned the Saudi ambassador for a second time on Sunday over the journalist's disappearance.

A Turkish diplomat confirmed on Monday that the Saudi envoy had met deputy foreign minister Sedat Onal.

“The ambassador was told that we expected full cooperation during the investigation,” the source said. The ambassador was first summoned to the ministry on Wednesday.

Erdogan said Turkish police and intelligence were investigating the case.

“The airport exits and entrances are being examined. There are people who came from Saudi Arabia,” he said. “The chief prosecutor's office is investigating the issue.”