Jamal Khashoggi is one of the Arab world's most prominent journalists and commentators.
Analysts say the diplomatic tip-toeing by both countries is a sign they fear the case could stoke increased tensions, cautious of further straining relations in the midst of power plays stemming from overlapping interests in the region.
"It points to the idea that whatever has happened to him, the Saudis - I mean, they've got some explaining to do", Corker was quoted as saying.
Dissident journalist and Washington Post contributor Khashoggi, 58, has been missing since last Tuesday after entering the Saudi consulate to gather documents for marriage. According to the Turkish government, Jamal Khashoggi was murdered by the Saudi Arabian government.
"We call for cooperation between Turkey and Saudi Arabia to conduct a prompt and impartial investigation into the circumstances of Mr. Khashoggi's disappearance and to make the findings public", United Nations human rights spokeswoman Ravina Shamdasani told reporters in Geneva.
David Rohde, executive editor of The New Yorker tweeted out, "The journalist Jamal Khashoggi had said that the Saudi crown prince, Mohammed bin Salman, has 'no tolerance or willingness to accommodate critics'".
In an essay in the Washington Post, Khashoggi's fiancée, Hatice Cengiz, implored US President Donald Trump and first lady Melania to "help shed light on Jamal's disappearance".
Sen. Bob Corker (R-TN), for one, was at least calling for an explanation from the Saudis on Tuesday, which Trump had failed to do.
Protector of journalists? Turkey is in the unusual position of protesting the treatment of a foreign journalist on their soil - after having spent the last two years jailing journalists and shuttering independent media. As shocking as Khashoggi's case is, she said, her overriding concern is that Trump, with his frequent attacks on "the fake news media" in America, "sets the overall tone that the United States doesn't really value press freedom".
Secretary of State Mike Pompeo, in his own statement said that "we have seen conflicting reports on the safety and whereabouts" of Khashoggi.
Saudi Arabia Wasn't Always This Repressive. A Saudi-led coalition has been at war with Yemen's Iran-aligned Houthi rebels since March 2015.
The unnamed woman, who is a Turkish citizen, called police when Khashoggi did not emerge at 5 p.m., after the consulate had officially closed.
A top Senate ally of Trump warned of a "devastating" impact on the USA alliance with Saudi Arabia if allegations are confirmed. The Sauds won't want any potential loose ends.
Turkish officials said Mr Khashoggi was killed on the premises and his body was then removed.
The Trump administration, from the president on down, is heavily invested in the Saudi relationship. The administration also relies on Saudi support for its Middle East agenda to counter Iranian influence, fight extremism and support an expected peace plan between Israel and the Palestinians.
Indication of those stakes came within four months of Trump taking office, when Saudi Arabia became his first destination on a presidential trip and he announced $110 billion in proposed arms sales.
"Opposition to the young crown prince in the ruling family will most likely grow", warned Ayham Kamel, the head of Mideast and North Africa research at the Eurasia Group. He has championed the three-year military campaign against Iran-backed Houthi rebels in Yemen that has pushed that nation toward starvation and caused many civilian deaths.
The Saudis have offered no evidence that he did leave.