Turkey will demand the extradition of 18 suspects in the Jamal Khashoggi killing from Saudi Arabia, state media has reported.

The dissident journalist disappeared after entering the Saudi consulate in Istanbul on October 2nd.

Both Turkey and Saudi Arabia have since said he was killed in the building, with Saudi authorities this week acknowledging for the first time that the murder was 'premeditated'.

18 people have been arrested by the kingdom in connection with the killing - three from the consulate, and a further 15 who are alleged to be part of a hit squad who flew to Istanbul to carry out the killing.

According to the Anadolu news agency, Turkish prosecutors are now calling for the extradition of the suspects over "charges of planned and deliberate murder with monstrosity and torture".

Earlier this week, Turkish President Recep Tayyip Erdogan said the country will continue to examine and investigate the killing as it took place "within the borders of Turkey", even though the consulate is considered Saudi Arabia's territory.

Meanwhile, Mr Khashoggi's fiancee has said the writer had concerns about entering the consulate in Turkey.

In this image from TV, Hatice Cengiz, who is Turkish, reacts during an interview on Turkish television channel HaberTurk. Picture by: HaberTurk/AP/Press Association Images

In an interview on broadcaster Habertürk and translated by Reuters, Hatice Cengiz said: “I know he had questions in mind about whether something untoward could actually happen at the consulate.

“He thought Turkey is a safe country and if he would be held or interrogated, this issue would be swiftly solved.”

She added that she had turned down an invitation from Donald Trump to visit the US, but she suggested she saw it as "a statement to win public favour".