"What's happening in Saudi Arabia is not normal," the typically close Trump ally and Republican senator said.
More than $100 million of weapons have been exported from the U.S. to Saudi Arabia over the past four years.
The Trump administration argues that Saudi Arabia needs emergency support to protect itself from Iran.
"There's a lot of money that historically has flowed from Gulf state individuals to the Trump family fortune," Senator Chris Murphy said, "and that has to be part of the explanation as to why they continue to bend over backwards to try to make the Saudis happy."
President Donald Trump's administration has created a potent anti-Iranian alliance in the Middle East.
Michael Wolff's new book "Siege" alleges senior White House adviser Jared Kushner made the comments about murdered Saudi dissident journalist Jamal Khashoggi.
The president's national security adviser also suggested Iran is still seeking a nuclear arsenal despite its adherence to the 2015 nuclear deal.
"Saudi Arabia is a strategic ally but the crown prince was, in my opinion, involved in the murder of Mr. Khashoggi and he's done a lot of other disruptive things," the Republican senator explained.
"It's not really about the titles. I've been fortunate to tell that story and I'll love to tell it again if I'm needed in that situation, but what's cool is to be able to do different stuff."
Houthi rebels in Yemen, backed by Iran, have claimed responsibility for the attack.
Iran has claimed innocence as regional tensions rise between Washington, its allies and Tehran.
"They have all shown an interest in dragging the United States into a conflict," Javad Zarif told Fox News Sunday. "I do not believe that President Trump wants to do that. I believe that President Trump ran on a campaign promise of not bringing the United States into another war."
A passenger aboard the Seven Seas Navigator cruise ship was evacuated to a hospital in Saudi Arabia after suffering with a medical emergency.
The same man who denounced the Iran nuclear pact as the "worst deal ever" is helping Iran's worst foe in the Persian Gulf get its feet on the nuclear ladder.
"Egyptian withdrawal is a huge blow to the Arab NATO idea," one expert said. "The Arab NATO will properly die not far in the future."
The Trump administration admitted it had made seven approvals for the sharing of technological information with Saudi Arabia without telling Congress.
"Every day that we go on without getting to the bottom of this matter is a day that we are putting hundreds, if not potentially thousands, of Americans at risk," the progressive Democrat from New York warned.
The names of six U.S. companies planning to supply nuclear equipment to Saudi Arabia have been kept secret.
"This will have negative effects on the Middle East peace process and security and stability in the region," the kingdom said in an official statement.
"Let's start with the fact that instead of solving Middle East peace, Jared nearly put us into a war in the region," Vicky Ward, author of "Kushner, Inc.," alleged.
"I believe in an inclusive foreign policy—one that centers on human rights, justice and peace as the pillars of America's engagement in the world, one that brings our troops home and truly makes military action a last resort," Representative Ilhan Omar wrote.
"No one can defeat a nation which pursues resistance," Iranian President Hassan Rouhani said in a televised address, claiming the U.S. and its allies were to blame for the country's poor economy.
Rex Tillerson, Trump's former secretary of state, said Jared Kushner had harmed the U.S. by influencing his father-in-law to back Saudi Arabia in its feud with Qatar.
"For Trump and his team, human rights is just another cudgel they wield opportunistically in service of a vision for the Middle East," Jamal Abdi, president of the National Iranian American Council, told Newsweek.
"Obama, he vetoed the bill that we needed to pass, and we came back and overrode his veto," Terry Strada said.