(CNN) US Secretary of State Mike Pompeo said Saudi Arabia's top leaders on Tuesday "strongly denied" any knowledge of what happened to missing journalist Jamal Khashoggi inside the Saudi consulate in Istanbul.

Pompeo said he met with King Salman, the King's son, Crown Prince Mohammed bin Salman, and Foreign Minister Adel al-Jubeir. In each of those meetings, "the Saudi leadership strongly denied any knowledge of what took place in their consulate in Istanbul," Pompeo said.

"We had direct and candid conversations. I emphasized the importance of conducting a thorough, transparent, and timely investigation, and the Saudi leadership pledged to deliver precisely on that."

"My assessment from these meetings is that there is serious commitment to determine all the facts and ensure accountability, including accountability for Saudi Arabia's senior leaders or senior officials," Pompeo said.

Saudi Arabia's King Salman, right meets with US Secretary of State Mike Pompeo in Riyadh.

The visit came as sources told CNN that the Saudis are preparing a report that will say the Washington Post columnist died in a botched interrogation intended to lead to his abduction from Turkey. On Tuesday, sources told CNN that a high-ranking official close to the crown prince's inner circle oversaw a botched interrogation that led to Khashoggi's death.

Pompeo will fly to Ankara Wednesday to meet with Turkish Foreign Minister Mevlut Cavusoglu, Nauert said.

Flurry of meetings

Pompeo was met at the airport in Riyadh on Tuesday by the Saudi foreign minister, and undertook a flurry of engagements with top officials throughout the day.

Pompeo's meeting with the King was relatively brief. Based on the arrival and departure times of his motorcade, CNN estimates the encounter can have lasted no more than 15 minutes. Pompeo met with the Crown Prince for about 35 to 40 minutes, and had dinner with him later.

Turkish authorities have said privately that Khashoggi was killed at the consulate in Istanbul as his fiancée, Hatice Cengiz, waited outside. Saudi Arabia has previously insisted he left the building alive, but Cengiz says she never saw him again.

On Tuesday, his family issued a statement in which they acknowledged for the first time that the journalist was no longer alive.

"The strong moral and legal responsibility which our father instilled in us obliges us to call for the establishment of an independent and impartial international commission to inquire into the circumstances of his death," they said in the statement.

The Turkish investigation

A Turkish official told CNN on Tuesday that Khashoggi's body had been cut up after he was killed in the consulate.

At a press conference in Ankara, the Turkish foreign minister said Saudi Arabia had not yet acknowledged its role in Khashoggi's disappearance.

"We didn't receive any confession or information from Saudi Arabia," Cavusoglu said, adding that Turkey expected to get more details about the Saudi position when Pompeo arrives in Turkey on Wednesday.

CCTV footage showed vehicles moving from the consulate building to the nearby consul general's residence on October 2. An anticipated search on Tuesday of the consul general's residence did not take place. In the meantime, the Consul General himself, Mohammed Otaibi, left Turkey on Tuesday, the semiofficial Anadolu news agency said. Turkish investigators said the search will take place Wednesday, according to state broadcaster TRT.

A Turkish forensic police officer works in Saudi Arabia's consulate in Istanbul on October 15, 2018, during the investigation over missing Saudi journalist Jamal Khashoggi.

On Monday, after CNN reporters saw a cleaning crew enter the main consulate building, Turkish officials conducted an investigation of the facility that lasted well into the evening.

By the time Turkish investigators gained access, a fresh coat of paint had been applied "everywhere" inside the building, a Turkish official told CNN Tuesday.

International pressure mounts

Saudi Arabia has been under intense international pressure to explain Khashoggi's apparent death after he visited the consulate on October 2 to obtain papers that would have allowed him to marry his Turkish fiancée.

The affair has created a diplomatic rift between Saudi Arabia and the West and led to international firms pulling out of a high-profile summit in Riyadh. The CEOs of three top banks -- Standard Chartered, HSBC and Credit Suisse -- announced their withdrawal from the conference Tuesday.

International Monetary Fund Managing Director Christine Lagarde's office said she is postponing her upcoming trip to the Middle East, which included a stop in Riyadh for the conference, known as "Davos in the Desert."

UK Opposition Leader Jeremy Corbyn said Khashoggi's disappearance calls into question the close relationship many Western countries have with Saudi Arabia and called for an immediate suspension of arms trade with the kingdom. He added that there needs to be an international investigation into the events in Turkey, describing it as an "abominable tragedy."

During Pompeo's visit, President Trump called the crown prince and the King's son "conveyed that a serious and credible investigation is already underway, Pompeo said.

"He pledged that the work of the Saudi public prosecutor will produce a full and complete conclusion with full transparency for the world to see."

United Nations human rights chief Michelle Bachelet called on Riyadh to lift immunity -- bestowed by the Vienna Convention on Consular Relations -- on its diplomatic premises, given the seriousness of the allegations leveled against Saudi Arabia.

"Under international law, both a forced disappearance and an extrajudicial killing are very serious crimes, and immunity should not be used to impede investigations into what happened and who is responsible," Bachelet said in a statement released Tuesday.

In the United States, Attorney General Jeff Sessions left open the door to potential US involvement when asked about Khashoggi's disappearance. He would offer no additional information and he would not comment on the credibility of the investigation.

"The matter is being given serious evaluation," he said.