The Saudi public prosecutor on Thursday said the murder of Khashoggi, a Washington Post columnist and critic of the kingdom's de facto ruler Crown Prince Mohammed bin Salman, was premeditated, revising previous statements that his death was unintended.
A columnist for The Washington Post, Khashoggi was last seen on October 2 when he entered the Saudi Consulate in Istanbul.
In a speech timed to coincide with the start of the three-day global business conference, Turkish President Recep Tayyip Erdogan rejected the Saudi narrative and said Khashoggi's murder was planned in Riyadh.
Turkish media have also published a security camera image allegedly showing a vehicle belonging to the Saudi Consulate "scouting" a forest in the outskirts of Istanbul before Khashoggi was killed.
Ilnur Cevik, an adviser to Turkish President Recep Tayyip Erdogan has accused Saudi Crown Prince Mohammed bin Salman of having Khashoggi's "blood on his hands".
Trump has also insisted that killing will not interfere with USA arms sales to Saudi Arabia, citing a $110bn deal with Riyadh he announced a year ago. "Everyone connected to the murder of the Saudi journalist needs to be investigated, tried in Turkey". Asked about the crown prince, though, Trump said, "Well, the prince is running things over there more so at this stage".
Mr Erdogan also confirmed that a body double of Khashoggi was used as a decoy after he was killed, after CCTV footage emerged on Monday of a man wearing the Washington Post columnist's dress shirt, suit jacket and trousers.
In the USA he wrote a monthly column in the Washington Post in which he criticised the policies of Crown Prince Mohammad bin Salman.
News of the call appeared to calm growing speculation that Turkey was edging toward implicating the crown prince, whose ambitions for a modernized Saudi Arabia have been undermined by his penchant for making enemies at home and overseas.
Turkish forensic teams have searched the Consulate, the consul general's official residence as well as vehicles belonging to the consulate as part of their probe into Khashoggi's disappearance and death.
Khashoggi, 59, hasn't been seen since he went into the Saudi consulate in Istanbul on October 2 to arrange paperwork for his upcoming wedding.
'She said the Home Secretary is taking action against all suspects in the murder of Mr Khashoggi to prevent them entering the UK. The State Department has already announced it will revoke the visas of 21 Saudis suspected to be connected to Khashoggi's death.
After more than two weeks of near silence, Saudi Arabia on Saturday admitted that Khashoggi was killed in its Istanbul consulate, saying it was an unauthorised operation - a claim other countries have rejected.
Salah and family expressed "great thanks" to the crown prince and his father King Salman, according to state media, and they expressed their condolences.
Saudi authorities first insisted the journalist Jamal Khashoggi came out of their Istanbul consulate alive.
Merkel also raised the dire humanitarian situation in Yemen during the call and urged Saudi Arabia to ensure access for humanitarian aid.