The case surrounding Jamal Khashoggi, the missing Washington Post columnist who disappeared after entering a Saudi consulate in Istanbul, raised more concerns after mounting evidence suggested he was murdered.
He declined to comment on Khashoggi's possible fate, but said "we can not let this happen; to reporters, to anybody".
"We're monitoring this very closely, this situation very closely, and we are working closely with [the] State Department", Mattis said.
"Something as serious as the assassination of a very senior, respected journalist in a foreign country's territory is not something we should turn a blind eye to", Professor Saul said.
Pro-government Turkish daily Sabah on Wednesday published preliminary evidence from investigators it said identified a 15-member Saudi intelligence team involved in Khashoggi's disappearance.
Trump told reporters a day earlier that he had raised Khashoggi's case with Saudi Arabia "at the highest level" and a couple of times in recent days and said he and his wife expect to invite Cengiz to the White House soon.
Corker tells The Associated Press that information he has reviewed suggests that Jamal Khashoggi was killed on October 2, the day he went to the Saudi consulate in Istanbul. There is no footage of him leaving.
Saudi Arabia denies journalist killed at consulate in Turkey
Those policies are all seen as initiatives of the crown prince, who has also presided over a roundup of activists and businessmen. DailyMail.com said a friend of the journalist revealed that Mr Khashoggi's encrypted messages had been read after he vanished.
Paul said he hopes Khashoggi's disappearance " motivates everybody to reassess our kinship and everything we do with Saudi Arabia".
It gives the White House 120 days to "determine whether a foreign person is responsible for an extrajudicial killing, torture, or other gross violation of internationally recognized human rights against an individual exercising freedom of expression" and to report back to the Foreign Relations Committee with a decision on how it plans to act.
USA intelligence officials reportedly intercepted communications that the Saudis discussed a plan to lure and capture Khashoggi before his disappearance.
Saudi Arabia denies involvement in the disappearance of Khashoggi, a former insider in Saudi government circles who has been living in self-imposed exile in the United States for the past year after fleeing a crackdown on intellectuals and activists in the country. Erdogan asked. "If a bird flew, if a mosquito appeared, these systems would catch them and (I believe) they (the Saudis) would have the most advanced of systems".
Trump, and son-in-law Jared Kushner, have been personally close to Mohammed bin Salman, since turning to Saudi Arabia as a pivotal ally in the Middle East against Iran. The footage shows Khashoggi entering the consulate on October 2. His disappearance has triggered a widening investigation by Turkish authorities, amid fears the journalist was killed inside the consulate. We have a country that's doing probably better economically than it's ever done before.
Khashoggi had, however, voiced distrust of the Saudi officials, and said they were unlikely to keep their words.
"Saudi Arabia is a key partner in the global fight against terrorism and transnational crime", an AUSTRAC spokesman said, citing "strict provisions" against releasing information that went against Australia's policies or aims.
Yet Yasin Aktay, an adviser to Erdogan, wrote in a newspaper column today that "bashing Saudi Arabia is meaningless and useless" because "Turkey and Saudi Arabia are two nations that need each other".