US Secretary of State Mike Pompeo will emphasise the need for accountability and credibility in the investigation of Khashoggi's death during a visit next week to the Middle East, including to Riyadh, the official said.
Mr. Pompeo will also visit Jordan, Egypt, Bahrain, United Arab Emirates, Qatar, Oman and Kuwait as part of his January 8 to January 15 trip, the State Department said in a statement. Iraq is said to be on the list, although no confirmation has been made by the state department due to security concerns, according to Politico.
The CIA has assessed that the killing was ordered by the crown prince, Mohammed bin Salman, a conclusion endorsed by the US Senate, but Trump and his senior officials, including Pompeo, have continued to insist the evidence against the prince, a key partner in the administration's Middle East policy, is conclusive.
The trip, scheduled for January 8-15, will take place less than a month after President Donald Trump's surprise decision to pull U.S. troops out of Syria.
"We may never know all of the facts surrounding the murder of Mr Jamal Khashoggi".
"The Iranian regime is the unsafe actor in the region", the State Department official said.
Pompeo will also visit Israel and Turkey, following in the footsteps of Trump national security adviser John Bolton, who will arrive in the area Friday.
"We have no timeline for our military forces to withdraw from Syria", an unnamed official confirmed in a telephone news briefing, cited by Politico.
It is also seeking a solution to the three-year-old war in Yemen in which a Saudi-led, US-supported coalition has battled with Iran-supported Huthi rebels over control of the country.
Mr. Khashoggi, a US -based Washington Post journalist from Saudi Arabia who had become a critic of the kingdom's Crown Prince Mohammed bin Salman, was last seen entering the Saudi consulate in Istanbul on October 2.
Both sides recently agreed to a ceasefire in the port city of Hodeida while United Nations envoy Martin Griffiths seeks to bring about a new round of talks between them.
The crown prince has famously cozied up to tech industry elites as oil-fueled Saudi wealth became the biggest funding source for USA companies, including Uber, Twitter, Tesla, DoorDash, Slack and Nvidia, among others.