Riyadh, Saudi Arabia -- U.S. Secretary of State Mike Pompeo held talks in Saudi Arabia Monday on a range of Mideast crises, topped by the conflicts in Syria and Yemen, threats from Iran and the Saudi response to the killing of Washington Post columnist Jamal Khashoggi last year.

Pompeo met with Saudi King Salman and Crown Prince Mohammed bin Salman on the latest stop of his Middle East tour that has so far been dominated by questions and concerns about the withdrawal of U.S. troops from Syria. The State Department said Monday that Pompeo would cancel his planned final stop in Kuwait on Tuesday due a death in his family. He will still travel to Oman later Monday.

In Riyadh, the Saudi-led fight against Iranian-backed rebels in Yemen, where the situation has been deemed the world's worst humanitarian crisis, will be a major agenda item, as well as holding perpetrators accountable for Khashoggi's slaying.

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Pompeo told the crown prince that his Middle East journey, which has taken him to Jordan, Iraq, Egypt, Bahrain and the United Arab Emirates, had been "good" so far.

"I want to talk to you about a couple of places we've been. We think we learned a lot along the way that will be important going forward," he said.

The prince replied that the Saudis would "try to add more positivity, as much as we can."

Speaking with senior Saudi officials on his arrival in Riyadh late Sunday, Pompeo stressed the importance of supporting a political solution to end Yemen's civil war and "the need for continued regional efforts to stand against the Iranian regime's malign activity and to advance peace, prosperity, and security," the State Department said.

U.S. wants "full and complete" accountability

The department said Pompeo also made clear the importance of a credible investigation into Khashoggi's killing at the Saudi Consulate in Istanbul in October. Pompeo "emphasized the importance of Saudi Arabia continuing its investigation into the murder of Jamal Khashoggi in order to ascertain facts, assess information, and hold those responsible accountable."

The relationship between Riyadh and Washington remains tense following Khashoggi's brutal slaying and dismemberment at the consulate.

The CIA has intelligence substantiating an assessment that the crown prince ordered Khashoggi's killing. The CIA's assessment appeared to be largely based on the control held by bin Salman. In other words, the thinking is the murder could not have been carried out without the knowledge of bin Salman, often referred to by his initials, MBS.

A U.S. intelligence official told CBS News the president was provided with the intelligence community's assessment on the matter, but near the end of December, President Trump vowed to stand by the Saudis regardless of any final conclusions by the CIA. He released a statement saying, "Our intelligence agencies continue to assess all information, but it could very well be that the Crown Prince had knowledge of this tragic event – maybe he did and maybe he didn't!"

He added, "That being said, we may never know all of the facts surrounding the murder of Mr. Jamal Khashoggi...the United States intends to remain a steadfast partner of Saudi Arabia to ensure the interests of our country, Israel and all other partners in the region."

In protest over the president's handling of the matter, the U.S. Senate approved a bipartisan resolution that put the blame for the killing of Khashoggi squarely on the Saudi crown prince. U.S. lawmakers also demanded America pull back its support of the Saudi-led war in Yemen.

A photo posted to Twitter by the Kingdom of Saudi Arabia's Foreign Ministry shows U.S. Secretary of State Mike Pompeo walking with Crown Prince Mohammed bin Salman on Jan. 14, 2018, in Riyadh, Saudi Arabia. Twitter/Handout

"We will continue to have a conversation with the crown prince and the Saudis about ensuring that the accountability is full and complete with respect to the unacceptable murder of Jamal Khashoggi," Pompeo told reporters in Qatar on Sunday before heading to Riyadh. "We'll continue to talk about that and make sure we have all the facts so that they are held accountable certainly by the Saudis, but by the United States as well, where appropriate."

The Qatar standoff



The ongoing dispute between Qatar and four of America's other close Arab partners will also feature in Pompeo's talks as it continues to be a major hindrance in a U.S.-led effort to unite the Gulf Arab states, Egypt and Jordan in a military alliance to counter Iran.

Bahrain, Egypt, Saudi Arabia and the United Arab Emirates began a boycott of Qatar in June 2017, alleging Qatar funds extremist groups and has too-cozy ties to Iran.

Qatar has long denied funding extremists, but Doha shares a massive offshore natural gas field with Tehran that gives its citizens the highest per-capita income in the world. It restored diplomatic relations with Iran after the crisis erupted, marking a setback for Saudi Arabia, which views the Shiite power Iran as its main regional rival.

A similar dispute involving Qatar erupted in 2014. But this time positions have hardened against Qatar, whose support for Islamist opposition groups has angered the Arab nations now boycotting it.

However, comments in Doha by Pompeo and Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman Al Thani gave no sense of any movement in the ongoing diplomatic crisis with Doha.

Later, speaking to a U.S. Embassy staff member in Qatar who said her job was moving to the UAE due to the boycott's effects, Pompeo was even more frank.

"It's on everyone's mind and not at all clear that the rift is any closer to being resolved today than it was yesterday - and I regret that," Pompeo said.