ISTANBUL: Saudi Arabia's consul in Istanbul opened up his mission on Saturday in an effort to show that Jamal Khashoggi, who vanished four days ago, was not on the premises and said that talk of his kidnapping was baseless.

Reuters journalists toured the six-storey consulate in northern Istanbul which Khashoggi, a Saudi journalist residing in the US, entered on Tuesday to get documents for his forthcoming marriage. His fiancee, who had waited outside, said he never came out.

Saudi Arabia said he left the consulate on Tuesday after completing his paperwork.

"I would like to confirm that...Jamal is not at the consulate nor in the Kingdom of Saudi Arabia, and the consulate and the embassy are working to search for him," consul-general Mohammad Al-Otaibi said in an interview at the consulate.

"We are worried about this case."

Crown Prince Mohammed bin Salman told Bloomberg that Saudi authorities would allow Turkey to search the consulate, but Turkish officials have not yet entered the premises.

Al-Otaibi said there were no legal charges against Khashoggi at the consulate, and he gave a tour of the building to Reuters to demonstrate that the missing journalist was not on the premises.

Opening cupboards, filing cabinets and wooden panels covering air conditioning units, Al-Otaibi walked through the six floors of the building including a basement prayer room, offices, visa counters, kitchens and toilets as well as storage and security rooms.

He said the consulate was equipped with cameras but they did not record footage, so no images could be retrieved of Khashoggi entering or leaving the consulate, which is ringed by police barriers and has high security fences topped with barbed wire.

The building has two entrances at the front and back, and Al-Otaibi said Khashoggi could have left from either side.

"If those who say he was kidnapped are focusing on his being in the mission, these are just rumours that have no proof," he said. "And we unfortunately regret some of the statements that have been made by Turkish officials who insist that (Khashoggi is) in the consulate ... without it being built on facts."

The spokesman for Turkish President Tayyip Erdogan's AK Party vowed that authorities would uncover the whereabouts of Khashoggi and the details of his disappearance, saying the case was highly sensitive for Turkey.

Al-Otaibi said authorities in the two countries were in contact. "Let us leave some time and a chance for both sides to see results".

The idea that Khashoggi may have been abducted at the consulate was "disgusting", he said. "The idea of kidnapping a Saudi citizen by a diplomatic mission is something that should not be put forward in the media."