"We write to urge you to personally raise the issue of Virginia resident Jamal Khashoggi's disappearance and welfare with the governments of Saudi Arabia and Turkey".
There will be "hell to pay" if Saudi Arabia killed a missing Washington Post journalist, a senior senator tersely warned Wednesday. His fiancée, waiting outside, said he never emerged and Turkish sources said they believe Khashoggi was killed in the building.
Saudi Arabia has called the claims baseless but has not provided any security camera footage of Khashoggi leaving the consulate.
"Victims of the Arab world's authoritarian regimes seek leadership from the USA and DAWN intends to provide such leadership", the organization wrote in a statement listing its core principles.
Khashoggi had, however, voiced distrust of the Saudi officials, and said they were unlikely to keep their words.
In Washington, State Department spokeswoman Heather Nauert said that the Saudi ambassador to the US was travelling to Saudi Arabia, and that the USA expects him to provide information about the Khashoggi case when he returns.
In a letter to President Donald Trump Wednesday, senators invoked the Global Magnitsky Act of 2016 to seek an investigation in the case of Jamal Khashoggi, who hasn't been seen since he entered the Saudi consulate in Istanbul last week.
Saudi Arabia has strongly rejected the accusation.
On his first worldwide trip as president, Trump visited Saudi Arabia and announced $110 billion in proposed arms sales.
The case has sparked outrage from human rights and journalism groups and threatens to harm ties between Saudi Arabia and the United States, which has demanded answers from the kingdom over the disappearance.
The Post, citing anonymous US officials familiar with the intelligence, says Saudi Crown Prince Mohammed bin Salman ordered an operation to lure Jamal Khashoggi from his home in Virginia to Saudi Arabia and then detain him.
Khashoggi was last seen visiting the Saudi consulate in Istanbul last week, and Turkey says he may have been murdered there. "I don't want to prejudge, but if it goes down the road that I'm anxious about it going down, contempt will be met with contempt", he said.
Sabah newspaper published the names and years of birth of 15 Saudis it said arrived at Istanbul's Ataturk airport on October 2.
He further stressed that he wants to end arms exports if there's "any indication" the Saudis are "implicated in killing this journalist that was critical of them".
Trump, whose first overseas trip as US president was to the kingdom and whose son-in-law Jared Kushner has close ties to Prince Mohammed, said Tuesday he had not yet talked to the Saudis about Khashoggi, "but I will be at some point".
Almost two hours later, the video shows two vehicles with diplomatic plates -a luxury black sedan and a black Mercedes VITO van- leave through the police barricades outside the consulate. "Although this incident could potentially fuel a political crisis between the two nations, let us not lose sight of the human aspect of what happened".
Khashoggi was a former government adviser who fled Saudi Arabia in September 2017 and lived in the United States fearing arrest back home.
Meanwhile, Turkish television channels have run CCTV footage, which they say shows the 15 alleged Saudi officers during their time in Istanbul. "Right now, I don't think we're prepared to do that unless Congress tries to force the administration's hand because there is incontrovertible evidence that the Saudis kidnapped and or killed Jamal Khashoggi", Riedel added.
The Washington Post said there are USA intelligence intercepts of Saudi officials discussing the plan.
On Tuesday, Turkey's Foreign Ministry announced that Turkish authorities were to search the Saudi consulate in Istanbul but did not specify when.
But if it becomes clear that he ordered the assassination of Khashoggi or was connected to it in some way, it will provoke an outcry on Capitol Hill; embarrass USA executives, dozens of whom are flocking to Riyadh for a conference next week where the crown prince is scheduled to speak; and put Kushner, who was once himself a newspaper publisher, in an extremely awkward position.