U.S. Secretary of State Mike Pompeo is meeting Monday in Riyadh with Saudi Arabia's King Salman and Saudi Foreign Minister Yusuf bin Alawi bin Abdullah, after urging other Saudi officials to continue a proper investigation into the killing of journalist Jamal Khashoggi.Pompeo is near the end of a trip to the Middle East in which he has been seeking to reassure allies about the pullout of U.S. troops from Syria and to seek support for U.S. efforts to get Iran to change what the Trump administration calls its malign behavior.Those topics were on the agenda Sunday during an hour-long meeting Pompeo had with Saudi Minister of State for Foreign Affairs Adel al-Jubeir.The State Department said Sunday they agreed about the need "for continued regional efforts to stand against the Iran regime's malign activity," and also talked about the situations in Syria, Yemen, Lebanon, Libya and Afghanistan.On Khashoggi, Pompeo stressed the need for a probe that holds responsible those accountable.Khashoggi was killed when he visited the Saudi consulate in Istanbul, Turkey in October. Initially Saudi Arabia said he safely left the site on his own, but later admitted he was killed there in what Saudi officials called a rogue operation.Turkey said the order to kill the Washington Post journalist came from the highest levels of the Saudi government but Saudi officials maintain it was not ordered by Saudi Crown Prince Mohammed bin Salman."We will continue to have a conversation with the crown prince and the Saudis about ensuring the accountability is full and complete with respect to the unacceptable murder of Jamal Khashoggi," Pompeo said earlier Sunday after a meeting in Doha with Qatari Foreign Minister Sheikh Mohammed bin Abdulrahman Al Thani.Pompeo flew to Riyadh after meetings in the Qatari capital of Doha, following stops in Jordan, Iraq, Egypt, Bahrain, and the United Arab Emirates during a weeklong trip of the Middle East. During the earlier joint press conference with al Thani, Pompeo also urged the Gulf countries to end a political rift in which Doha has been boycotted by neighboring former allies for months."President Trump and I both believe the ongoing dispute in the region has gone on too long," Pompeo said.The U.S., which appeared initially to support the boycott when it began in 2017, has since been unsuccessful in negotiating between Qatar and the Gulf Cooperation Council (GCC). All six member states of the GCC (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates) are U.S. allies."We're hopeful that unity in the GCC will increase in the days and weeks and months ahead," Pompeo said.In June 2017, Saudi Arabia, Bahrain, the United Arab Emirates (UAE) and Egypt imposed sanctions on Qatar, accusing Doha of financing extremist groups and aligning with Iran, the Gulf Arab states' rival. Qatar has denied the allegations.