FILE - People hold signs during a protest at the Embassy of Saudi Arabia about the disappearance of Saudi journalist Jamal Khashoggi. in Washington. (Associated Press)

Turkish officials have an audio recording of the alleged killing of writer and activist Jamal Khashoggi from the Apple Watch he wore when he entered the Saudi Consulate in Istanbul over a week ago, a Turkish newspaper reported Saturday.

The assertion by the pro-government Sabah newspaper, through which Turkish security officials have leaked information on the Khashoggi case, is reportedly ratcheting up the pressure on Saudi Arabia to explain what happened to the missing man.

The writer, who has written critically about Saudi Crown Prince Mohammed bin Salman, vanished after going into the consulate on Oct. 2. The kingdom has maintained the allegations against it are "baseless," though an official said on Saturday — the date is also Khashoggi's 60th birthday — acknowledged for the first time that some believe the man was killed by the kingdom.

President Trump, who has enjoyed close relations with the Saudis since entering office, expressed concern Saturday about Khashoggi's fate and the lack of concrete answers.

"Our first hope was that he was not killed but maybe that's not looking too good from what we hear but there's a lot to learn, there really is," Trump said at the White House while welcoming back American pastor Andrew Brunson, freed after nearly two years of detention in Turkey, according to a report in The Associated Press.

Turkish authorities recovered the audio from Khashoggi's iPhone and his iCloud account, the newspaper said. He reportedly handed his phones to his fiancée before entering the consulate.

The newspaper also alleged Saudi officials tried to delete the recordings, even using his finger in the attempt. However, as noted by AP, Apple Watches do not have a fingerprint ID unlock function like that included on iPhones.

The Associated Press contributed to this report.