US intelligence intercepts of Saudi officials suggested that Saudi Crown Prince Mohammed bin Salman was behind the disappearance of Washington Post columnist Jamal Khashoggi and that Khashoggi may have been killed during a botched kidnapping attempt.
Trump declined to say whom he talked with in the Saudi government.
Turkish officials fear Khashoggi was killed by the Saudis after he walked into the consulate, though they haven't offered any evidence to support that.
Trump also said USA investigators were in Turkey, working with the Turks and Saudis, to probe the disappearance.
"What has reportedly happened in Turkey around the disappearance of journalist Jamal Khashoggi, if proved true, would clearly change the ability of any of us in the West to do business with the Saudi government", Branson said in a statement.
President Donald Trump: "I'd rather not say, but at a very high level, the highest level".
Senate Foreign Relations Committee chairman Bob Corker says he has reviewed U.S. intelligence reports suggesting that Khashoggi was killed on October 2, the day he went to the consulate.
"His wife wrote us a letter, addressed to my wife and myself and we are in contact with her now".
He said he and his wife, Melania, expect to invite Cengiz to the White House soon. "Well, I have to find out who did it, but people saw him go in...but they didn't see come out, as they understand it and we're going to take a very serious look at it". We're looking at it very strongly.
But in his first extensive remarks about Khashoggi's case, Trump warned it is "a very sad situation". "This is a bad situation. And tell us what he knows too", he tweeted last week. "We can't let this happen". The fallout could reshape alliances in the region, where the U.S.is seeking to stabilize Syria, contain Iranian weapons development and support a Saudi-led coalition in Yemen's civil war.
Trump, in an interview with the Fox News "Fox & Friends" program, also called US-Saudi relations "excellent".
"This is unprecedented. I've never seen or heard of anything like this", Courtney Radsch, advocacy director at the Committee to Protect Journalists, said of the disappearance of Jamal Khashoggi.
Decades of close U.S. -Saudi relations, which have only intensified under Trump, appeared in jeopardy by the suggestion of a carefully plotted murder of a government critic.
U.S. Secretary of State Mike Pompeo followed up with his own call to the crown prince, who had forged close ties to the administration, especially Kushner.
She also said that the United States government welcomed a "thorough" investigation and has been in contact with the Saudi Ambassador to the United States, who is now headed back to Saudi Arabia.
The Trump administration sharply upped the pressure, reversing an initially low-key response after Washington Post contributor Khashoggi vanished on October 2. Even under the Obama administration, which had hard relations with Riyadh compared with Trump, there were some $65 billion in completed arms sales. Among them was a forensics expert, it says.
Turkish media released police CCTV surveillance videos said to be of a Saudi "assassination squad".
Riyadh insisted the Khashoggi left the building and called the murder claims "baseless".
Reports about the USA appointing investigator over the disappearance of Saudi journalist Jamal Khashoggi are untrue, said Turkish diplomatic sources on Thursday.
On Wednesday, State Department spokesman Robert Palladino said the United States "had no advance knowledge" of such a plan.
Citing a person familiar with the case, the report said USA intelligence intercepted the communications of Saudi officials elaborating on a plan to seize Khashoggi.