Washington (CNN) Secretary of State Mike Pompeo pushed to buy time for Saudi Arabia Thursday, urging patience as they conduct an investigation into the disappearance of Jamal Khashoggi and leaving open the possibility the White House will do little or nothing in response.

"I told President Trump this morning that we ought to give them a few more days to complete that, so that we, too, have a complete understanding of the facts surrounding" what happened to the Washington Post journalist, Pompeo told reporters at the White House after a meeting with the President.

"At which point, we can make decisions about how or if the United States should respond to the incident surrounding Mr. Khashoggi."

The top US diplomat added a caveat that he and Trump have been underscoring frequently in the last few days. "We have a long strategic relationship with Kingdom of Saudi Arabia," Pompeo said. "They're an important partner. We need to be mindful of that as well."

Pompeo met with the President as the Trump administration is desperately trying to manage raging criticism from lawmakers and growing international pressure to act as evidence mounts tying the father of four's disappearance to the Saudi royal family. He entered the Saudi consulate in Istanbul on Oct. 2 and has not been seen since.

Treasury Secretary Steven Mnuchin announced Thursday that after consulting with Trump and Pompeo, he would not attend a high-level investment conference in Saudi Arabia. His decision had been closely watched, as other government and business leaders have canceled in droves. No other US officials will attend in Mnuchin's place, an administration source told CNN.

The top US diplomat returned Wednesday from Riyadh, where he met with King Salman and the kingdom's de facto ruler, 33-year-old Crown Prince Mohammed bin Salman.

That meeting drew scathing criticism for the warm smiling images of Pompeo with the Saudi royals and for Pompeo's declaration afterward that he didn't want to talk about "facts" and that in his meetings, the Saudis "didn't want to either."

On Thursday, Pompeo once again declined to get into the known details of Khashoggi's disappearance and alleged killing, instead saying the US will "allow the facts to unfold." To date, the top US diplomat has not referred to the possibility that Khashoggi is dead, but only that he is missing.

"There are lots of stories out there about what has happened. We're just going to allow the process to move forward, allow the facts to unfold and as they unfold. As we make a determination for ourselves about what happened there based on the facts that are presented to us, the United States will determine what the appropriate response might be," Pompeo said.

Feeling the heat

As the crisis draws attention to Trump's business ties to Saudi Arabia and the relationship between the crown prince and Trump's son-in-law and senior adviser Jared Kushner, Trump and Pompeo are stressing the need for patience, for the Saudis to complete their own investigation and the importance of US ties with the kingdom.

Trump has emphasized the crown prince's "strong" denial of any knowledge about Khashoggi's disappearance on October 2, the day a Saudi hit squad allegedly arrived at the consulate. He has also insisted he is not giving "cover" to Saudi Arabia to come up with an explanation.

But the White House is beginning to show some discomfort with the rising level of anger from Republicans as well as Democrats. On the international stage, a slew of corporations and global leaders have signaled their disapproval by withdrawing from Saudi Arabia's Future Investment Initiative, dubbed "Davos in the Desert."

While Trump in particular has been strongly supportive of the Saudis and blasted their critics, the administration signaled a slight shift in its approach to the crisis Wednesday, with a source telling CNN that Pompeo's meeting with the crown prince was tougher than it appeared to be.

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Behind the smiles, which dropped as soon as the photo op ended, the source said, Pompeo told the royal his future as King depends on his handling of Khashoggi's suspected murder and that he had to "own" what happened, even if he hadn't known.

The source, who spoke on condition of anonymity to describe diplomatic meetings, said Pompeo also made it clear to the crown prince that the Saudis had to get their investigation done very quickly. The top US diplomat stressed that time is short and that the Saudis have to deal with the people involved sharply, the source said.

Pompeo went on to tell the prince "bluntly that if they don't, the US will have to deal with this," the source said, and "will take action because the world will demand it and that President Trump's hand will be forced by the global pressure."

The Trump administration is relying on Saudi Arabia for a slew of crucial foreign policy priorities, from funding for Syria's reconstruction and the fight against extremists there, to getting Saudi financial support for a Middle East peace plan.

Most crucially, the White House needs Saudi Arabia to keep international oil markets steady as they confront Iran and introduce new energy sanctions against countries that purchase Iranian oil starting November 4.

Damning details

But as details continue to emerge about Khashoggi's suspected murder inside the Saudi consulate in Istanbul -- and sources float the possibility that blame will fall on a "rogue" operative -- the administration's effort to defend Saudi Arabia is creating pushback and raising questions about Trump's potential conflicts of interest.

Some lawmakers are calling for an independent international inquiry as others are asking the President to report to Congress within a month about any personal financial ties he might have to the Kingdom that might create conflicts of interest.

"According to public reports, the Trump Organization for decades has maintained business relationships with the government of Saudi Arabia and members of the Saudi royal family," a group of Democratic senators wrote the President on Wednesday.

"Your recent statements, and public reports of increased spending by the Saudi government at Trump properties, raise significant concerns about financial conflicts of interest," the lawmakers wrote.

While Trump insisted this week he has no financial interests in Saudi Arabia, he has boasted publicly about money he's made from Saudi property investors and Saudis have poured money into Trump Hotels since the President's election.

A lobbying firm for Saudi Arabia paid more than $270,000 to the Trump International Hotel in Washington between October 2016 and March 2017, and The Washington Post has reported that Trump Hotels in New York and Chicago have benefited from a rush of visitors from Saudi Arabia in recent months.

Nebraska Sen. Ben Sasse became the latest Republican to raise concerns about Trump's handling of the Saudi matter, telling CNN's Christiane Amanpour that "I think we're going to need an international investigation" into Khashoggi's alleged death.

"This is not a small matter that will be swept under the rug," Sasse said, adding that he hoped Trump was listening to information from his intelligence services, "not just the arguments that are coming from Saudi officials."