U.S. Secretary of State Mike Pompeo on Tuesday met with Saudi Arabia's Crown Prince Mohammed, the man alleged to have ordered the interrogation and killing of journalist Jamal Khashoggi in Istanbul.

Pompeo landed in Riyadh and was immediately driven to meet King Salman over the crisis surrounding Khashoggi, who vanished two weeks ago during a visit to the Saudi consulate.

As he greeted the crown prince, Pompeo smiled and gleefully shook his hand—an act which some have seen as showing support to the regime which has increasingly cracked down on dissent in recent years.

While America's top diplomat posed for photos, senators in Washington were buzzing about harsh new sanctions in response to the killing.

Pompeo's arrival in Riyadh came just hours after Turkish forensic teams searched through the consulate to find evidence of what happened to the Saudi writer.

Turkish officials say they fear Khashoggi was killed and dismembered inside the consulate and told the Associated Press shortly after the summit that police found evidence in the building suggesting he was killed there.

Saudi officials previously have called the allegations 'baseless,' but reports last night suggested the kingdom may acknowledge the Washington Post writer was killed there in an 'interrogation gone wrong.'

U.S. Secretary of State Mike Pompeo smiles and shakes hands with Saudi Crown Prince Mohammed bin Salman in Riyadh today

Pompeo flew to the Saudi capital to discuss the disappearance of journalist Jamal Khashoggi where Crown Prince Mohammed bin Salman said the two countries were 'old, strong' allies

Khashoggi (pictured in December 2014) vanished after visiting the Saudi consulate on October 2 to collect divorce papers so he could marry his Turkish fiancee

Before meeting the crown prince, Pompeo met with the prince's father King Salman and the Saudi foreign minister

Saudi Arabia's King Salman greets U.S. Secretary of State Mike Pompeo in Riyadh on Tuesday. The pair are due to discuss the disappearance of dissident journalist Jamal Khashoggi

Mike Pompeo, left, begins his meeting with Saudi Arabia's King Salman in Riyadh today. Khashoggi vanished two weeks ago during a visit to the Saudi consulate

But an official said on condition of anonymity as he was not authorized to speak publicly about the investigation said that 'certain evidence' was uncovered during the forensic search of the consulate last night.

During his meeting today, Pompeo was told by the heir to the Saudi throne the U.S. and Saudi Arabia are 'old, strong allies.'

That alliance, however, has irked American senators who believe the Trump administration's handling of the Saudi kingdom is too kid-glovish in the face of serious human rights violations.

Riyadh has made commitments to spend $110 billion on U.S.-made military equipment in the next decade.

'I don't care how much money it is,' Florida Republican Sen. Marco Rubio said Tuesday on CNN. 'There isn't enough money in the world to purchase back our credibility on human rights and the way nations should conduct themselves.'

'Human rights is worth blowing that up,' Rubio said, 'and luring someone into a consulate where they're murdered, dismembered and disposed of is a big deal.'

South Carolina Republican Sen. Lindsey Graham, usually a reliable Saudi defender on the Senate floor, went further. On 'Fox & Friends,' he said he would use his position on the Foreign Relations Committee to 'sanction the hell out of Saudi Arabia.'

Florida Republican Sen. Marco Rubio said Tuesday that 'there isn't enough money in the world to purchase back our credibility on human rights,' and suggested 'blowing up' an arms deal with the kingdom

South Carolina Republican Sen. Lindsey Graham said he would use his position on the Foreign Relations Committee to 'sanction the hell out of Saudi Arabia'

'This guy is a wrecking ball,' Graham said of MBS. 'He had this guy murdered, in a consulate in Turkey. And to expect me to ignore it? I feel used and abused.'

'You know, we deal with bad people all the time, but this is in our face. I feel personally offended. ... This guy's got to go,' he said.

Mitch McConnell, the powerful Senate majority leader, told Bloomberg TV that 'it's good that the president sent the secretary of State to talk to the king. We need to find out what happened before deciding what kind of response is appropriate.'

Asked whether the U.S. would have 'some type of response' to Khashoggi's death, he said: 'I can’t imagine there won’t be, but I think we need to find out what happened.'

Saudi Arabia's consul to Istanbul today left the Turkish city bound for Riyadh on a scheduled flight, reports said, as Turkey prepared to search his residence in the probe into the disappearance of Khashogghi.

Consul general Mohammed al-Otaibi took off for Riyadh on a 2pm (GMT) flight from Istanbul, the Haber-Turk newspaper reported on its website.

The state-run Anadolu news agency also reported he had left Turkey, with the website of Ataturk International Airport showed a flight of flag-carrier Saudia took off for Riyadh at 2pm (GMT).

A statement from the Saudi Press Agency after the Pompeo meeting said: 'During the meeting, historical relationships between the two countries were reviewed, and current situations in the region and joint efforts being exerted towards them were discussed.'

Pompeo later thanked King Salman for his commitment to a thorough, transparent investigation of the Jamal Khashoggi disappearance, according to the U.S. State Department.

After his talks with the king, Pompeo met with his powerful son, Crown Prince Mohammed bin Salman, where the two will have dinner, a U.S. official said.

The prince told Pompeo in front of the media: 'We are strong and old allies. We face our challenges together—the past, the day of, tomorrow.'

Many commentators on Twitter criticized the way Pompeo greeted the crown prince when he was there to raise questions about an alleged murder.

Mike Pompeo (center left) meets with Saudi Foreign Minister Adel al-Jubeir (center right) in Riyadh ahead of talks with King Salman

U.S. Secretary of State Mike Pompeo (center) walks with Saudi Foreign Minister Adel al-Jubeir (center right) shortly after arriving in Riyadh this morning

Mike Pompeo as he leaves U.S. soil to fly for crucial talks with the Saudi King Salman over the alleged killing of Washington Post journalist Jamal Khashoggi

One woman posted on Twitter: 'Disturbing considering is meant to be there to demand answers about the brutal murder of a journalist and he is all giddy and smiles next to the perp.'

Another added: 'All smiles over a ruthless torture and murder.'

A post on social media said: 'Mike Pompeo is absolutely there to assist on a narrative to cover for MSB and his father. We must keep pressure on this admin to hold them responsible. The U.S. should not be for sale.'

Another added: 'How can he [Pompeo] shake the hand of the murderer? Because serves a president who calls for violence against journalists in his own country. To him, he is not shaking the hand of an enemy of freedom and democracy, he is shaking the hand of a like-minded buddy.'

Until yesterday, Riyadh had not allowed Turkish investigators to search the consulate—officially Saudi territory—with reports both sides were at odds over the conditions.

Last night technicians in forensic suits, gloves and covered shoes treated the diplomatic mission as a crime scene during their hours-long search, but it was not immediately clear what evidence they gathered.

As Pompeo disembarked from the plane in the Saudi capital he made no comments.

Pompeo arrived in the Saudi capital this morning to follow up Donald Trump's phone call with King Salman yesterday

Saudi Arabia's Foreign Minister Adel al-Jubeir (right), Interior Minister Prince Abdel Aziz bin Saud bin Nayef (second right), the desert kingdom's ambassador to the United States, Prince Khaled bin Salman (second left), and state minister Musaed bin Mohammed al-Aiban at the meeting

Pompeo walks with Saudi Foreign Minister Adel al-Jubeir in Riyadh as he is taken to meet King Salman at Al-Yamama Royal Palace

Pompeo, left, shakes hands with Saudi Foreign Minister Adel al-Jubeir after arriving today in the Saudi capital

Pompeo posed for pictures with Saudi Foreign Minister Adel al-Jubeir near pictures of the Saudi royal family

President Donald Trump dispatched Pompeo to speak to the monarch of the world's top oil exporter over Khashoggi's disappearance after speaking with King Salman yesterday.

Trump himself said without offering evidence that the slaying could have been carried out by 'rogue killers,' offering the US-allied kingdom a possible path out of a global diplomatic firestorm.

However any decision in the ultraconservative kingdom rests solely with the ruling Al Saud family.

Saudi Crown Prince Mohammed bin Salman, whom Khashoggi wrote critically about for The Washington Post and whose rise to power prompted the writer to go into a self-imposed exile in the United States, was absent from discussions.

Ayham Kamel, the head of the Eurasia Group's Mideast and North African practice said: 'The effort behind the scenes is focused on avoiding a diplomatic crisis between the two countries and has succeeded in finding a pathway to deescalate tensions.

'Riyadh will have to provide some explanation of the journalist's disappearance, but in a manner that distances the leadership from any claim that a decision was made at senior levels to assassinate the prominent journalist.'

Secretary of State Mike Pompeo with secret service personnel as he boards his plane to depart for Riyadh for talks over the disappearance of Jamal Khashoggi

Reports claim Mohammed bin Salman, crown prince and minister of defense of the Kingdom of Saudi Arabia did not order the interrogation of Jamal Khashoggi that 'went wrong'

Secretary of State Mike Pompeo heads to his plane at at Andrews Air Force Base to depart for meetings with Saudi Arabia's King Salman in Saudi Arabia today

A Turkish forensic police officer shoots video in a room of the Saudi consulate in Istanbul yesterday. The kingdom was said to be about to admit the journalist was killed in a botched interrogation

Cleaning personnel wait to enter Saudi Arabia's consulate before forensic Turkish forensic teams searched the building looking for clues

CNN reported that the Saudis were going to admit the killing had occurred but deny the king or crown prince had ordered it - which does not match what analysts and experts know about the kingdom's inner workings.

The New York Times reported that the Saudi royal court would suggest that an official within the kingdom's intelligence services—a friend of Prince Mohammed—had carried out the killing.

According to the reported claim, the crown prince had approved an interrogation or rendition of Khashoggi back to Saudi Arabia, but the intelligence official was tragically incompetent as he eagerly sought to prove himself.

Both reports cited anonymous people said to be familiar with the Saudi plans.

Saudi officials have not answered repeated requests for comment over recent days.

Saudi officials have been in and out of the building since Khashoggi's disappearance on October 2 without being stopped.

The UN human rights chief today called for the lifting of the immunity of officials who might be involved in Khashoggi's disappearance.

Michelle Bachelet said: 'In view of the seriousness of the situation surrounding the disappearance of Mr. Khashoggi, I believe the inviolability or immunity of the relevant premises and officials... should be waived immediately.'

Pompeo met with Saudi Foreign Minister Adel al-Jubeir before being taken to see Saudi Arabia's king

Mike Pompeo smiled as he received a gift from his hosts during his visit to Riyadh today

Pompeo and the Saudi Foreign Minister walk through the ornate halls of the Al-Yamama Royal Palace in Riyadh

Trump suggested Khashoggi may have been murdered by 'rogue killers' after he had a phone conversation with King Salman yesterday

Trump and Saudi Arabia's King Salman bin Abdulaziz Al Saud at the Arabic Islamic American Summit at King Abdul Aziz International Conference Center in Riyadh last year

Turkish police officers arrive at the Saudi Arabia's consulate in Istanbul last night as teams swept the building as part of the investigating in to the

Under the Vienna Convention, diplomatic posts are technically foreign soil that must be protected and respected by host countries.

Mechthild Prinz, an associate professor at the John Jay College of Criminal Justice who previously worked at the New York City's Office of the Chief Medical Examiner, said forensics tests like spraying luminol, a chemical mixture, can expose blood left behind.

She said: 'It depends on how well they cleaned it up. Obviously, you don't want anybody to have a chance to clean it up, but very often people do miss blood.'

When told a cleaning crew walked into the consulate before the team arrived, she replied: 'You saw that? Wow. That's going to be a problem.'

Turkey has wanted to search the consulate for days and permission apparently came after a late Sunday night call between King Salman and Turkish President Recep Tayyip Erdogan.

In statements after the call, both praised the creation of a joint Saudi-Turkish probe.

Turkish police officers gather as they prepare to enter the Saudi Arabia's consulate in Istanbul, with Turkish crime scene investigators sweeping through the building

Turkish police officers arrive to enter the Saudi consulate to search for clues into the disappearance of Jamal Khashoggi

A bouquet of flowers was left on the police barriers blocking the road to Saudi Arabia's consulate

The Turkish inspection team included a prosecutor, a deputy prosecutor, anti-terror police and forensic experts, the state-run Anadolu news agency reported.

Certain areas of the consulate were to remain off-limits, although officials would be able to inspect surveillance cameras, Turkish media reported.

Khashoggi has written extensively for the Post about Saudi Arabia, criticizing its war in Yemen, its recent diplomatic spat with Canada and its arrest of women's rights activists after the lifting of a driving ban for women.

Those policies are all seen as initiatives of Prince Mohammed, the son of King Salman, who is next in line to the throne.

Prince Mohammed has aggressively pitched the kingdom as a destination for foreign investment, but Khashoggi's disappearance has led several business leaders and media outlets to back out of the upcoming investment conference in Riyadh, called the Future Investment Initiative.

Turkish police officers prepare to enter the Saudi Arabia's consulate. Turkish crime scene investigators dressed in coveralls and gloves entered the consulate yesterday

Security guards walk outside Saudi Arabia's consulate in Istanbul yesterday as Saudi Arabia are expected to conduct a joint 'inspection' of the consulate, where Saudi journalist Jamal Khashoggi went missing nearly two weeks ago

Google Cloud CEO Diane Greene, Dara Khosrowshahi, CEO of Uber, a company in which Saudi Arabia has invested billions of dollars, billionaire Richard Branson, JPMorgan Chase & Co Chief Executive Jamie Dimon and Ford Motor Company Executive Chairman, Bill Ford, have all pulled out of the kingdom's upcoming high-profile conference dubbed 'Davos in the Desert.'

Trump previously warned of 'severe punishment' for the kingdom if it was found to be involved in Khashoggi's disappearance, which has spooked investors in Saudi Arabia and SoftBank, a Japanese firm that manages tens of billions of dollars for Saudi Arabia.

Trump's warning drew an angry response on Sunday from Saudi Arabia and its state-linked media, including a suggestion that Riyadh could wield its oil production as a weapon.

Dara Khosrowshahi, chief executive officer of Uber, has pulled out of the the Future Investment Initiative—dubbed 'Davos in the Desert'

The US-based Soufan Center slammed Trump's approach, saying the US-Saudi relationship 'since the ascendance of Crown Prince Mohammed bin Salman demonstrates the problem with basing relationships on personalities over principles.'

The U.S. president has been after King Salman and OPEC to boost production for weeks to drive down high crude oil prices, caused in part by the coming re-imposition of oil sanctions on Iran after the U.S. withdrawal from that's country's nuclear deal with world powers.

Despite being the world's largest oil exporter, selling a million barrels per day to the United States, Saudi Arabia would gain little from using 'black gold' as leverage, according to Jean-Francois Seznec, a Senior Fellow at the Atlantic Council's Center for Global Energy.

That 'would completely destroy its image as a "reliable supplier"' and undermine the king's powerful son, Crown Prince bin Salman, he said.