While both of them were smiling in front of the cameras, the meeting was in a much more serious tone as Pompeo insisted the case was not something Saudi Arabia would casually dismiss and that the truth behind the disappearance would come out eventually, the report said.
"I'm not giving cover at all", Trump said.
France joins a wave of countries and companies that have said they will boycott the Saudi event amid reports that the USA -based journalist was ambushed and killed within the consulate in Istanbul by Saudi agents.
Turkish officials say they fear that Khashoggi, a prominent Saudi journalist who had been in living self-imposed exile in the United States, was killed and dismembered after he entered the consulate. "That means I'm not going back to Saudi Arabia as long as this guy's in charge".
Russian President Vladimir Putin, meanwhile, took a dig at Washington, saying that "the USA holds a certain responsibility over what happened to him".
"This incident is unacceptable and clearly they have to answer questions specifically regarding this incident", Goldman Sachs CEO David Solomon told CNBC.
The Washington Post has previously cited unnamed United States and Turkish officials pointing to audio and video recordings that supposedly prove Khashoggi was killed inside the consulate and was then dismembered. Khashoggi went to the consulate seeking documents for his planned marriage to his Turkish fiancee, who was waiting outside, and was never seen again.
Trump did not say Thursday what he based his conclusion on.
USA secretary of state Mike Pompeo on Wednesday arrived in Ankara from Riyadh.
At around 4:40 pm (1340 GMT) a team of a dozen police and prosecutors, including forensics experts in white overalls entered the residence of the consul, who was at the consulate when the alleged assassination of Khashoggi took place, according to Turkish media. The official added Pompeo had warned him that it would be "very hard for you to be a credible king" without a credible investigation. The crown prince is next in line for the throne, which is held by his ailing, aged father King Salman.
In an announcement that sent stocks tumbling on Wall Street, Mnuchin said he had decided with President Donald Trump that he would "not be participating in the Future Investment Initiative summit in Saudi Arabia".
Mnuchin's decision is a relatively cost-free way for the U.S.to show it's taking a tougher stance against Saudi Arabia after Trump and Pompeo stressed that the U.S. -Saudi relationship is too significant to walk away from.