US secretary of state also calls on Gulf states to end political rift in the region

US Secretary of State Mike Pompeo on Sunday arrived in Riyadh, where he was scheduled to ask Saudi authorities to ensure the killers of journalist Jamal Khashoggi are held accountable.

The top US diplomat, on an extensive Middle East tour, embarked on his second politically sensitive visit to Saudi Arabia since Khashoggi's murder inside the country's Istanbul consulate sparked an international outcry.

"We will continue to have a conversation with the crown prince (Mohammed bin Salman) and the Saudis about ensuring the accountability is full and complete with respect to the unacceptable murder of Jamal Khashoggi," Pompeo told reporters in Qatar, before flying to Riyadh.

Khashoggi, a Washington Post contributor, was murdered on Oct 2 in what Saudi Arabia called a "rogue" operation, tipping the kingdom into a diplomatic crises and subsequently straining ties between Riyadh and Washington.

Pompeo's visit to Saudi Arabia, where he will be hosted by Crown Prince Mohammed bin Salman, is part of an extensive eight-day trip to Amman, Cairo, Manama, Abu Dhabi, Doha, Riyadh, Muscat, and finally Kuwait City.

US President Donald Trump has brushed aside international outrage to stand by Riyadh over the murder of Khashoggi.

Riyadh prosecutors have announced indictments against 11 people, and are seeking the death penalty against five of them. Prince Mohammed was exonerated by prosecutors.

During his visit to Qatar, Pompeo refused to comment on reports Washington had recently considered military action against Iran.

US media reported on Sunday that the White House National Security Council last year asked the US Department of Defense to provide military options to strike Iran, citing former US officials. This request, which many saw as unusual, raised deep concern at the Pentagon and the State Department.

Pompeo also called on Qatar and other Gulf countries to end the worst political rift in the region in years, which has seen Qatar diplomatically and economically isolated by neighboring former allies for the past 19 months. He said the rift had gone on for too long and was threatening regional unity needed to counter Iran.

Saudi Arabia, the United Arab Emirates, Bahrain and Egypt－all US allies－cut ties with Qatar in June 2017, accusing the country of supporting terrorist groups and seeking closer ties to Iran.

Qatar－also a US ally－denies the allegations and accuses those countries of seeking government change.

AFP, Reuters and Xinhua contributed to this story.