FILE PHOTO: Saudi Arabia's Crown Prince Mohammed bin Salman attends a graduation ceremony for the 95th batch of cadets from the King Faisal Air Academy in Riyadh, Saudi Arabia December 23, 2018. Bandar Algaloud/Courtesy of Saudi Royal Court/Handout via REUTERS

ANKARA (Reuters) - Republican U.S. Senator Lindsey Graham said on Saturday the relationship between the United States and Saudi Arabia cannot move forward until Saudi Crown Prince Mohammed bin Salman is “dealt with”, without being more specific.

Speaking in Ankara a day after meeting with Turkish President Tayyip Erdogan, Graham also said Congress will reintroduce sanctions against those involved in the killing of Saudi journalist Jamal Khashoggi.

“The relationship between the U.S. and Saudi Arabia cannot move forward until Crown Prince Mohammed bin Salman is dealt with,” Graham said.

Khashoggi was a prominent Saudi journalist and U.S. resident who wrote opinion columns for the Washington Post. He was killed in the Saudi consulate in Istanbul in October.

Riyadh initially denied knowledge of Khashoggi’s disappearance, then offered contradictory explanations, including that he was killed in a rogue operation.

Saudi officials have said the crown prince knew nothing of the killing. Saudi Arabia said last year that 21 Saudis were taken into custody in relation to the Khashoggi case, 11 of whom have been indicted and referred to trial.

Crown Prince Mohammed’s top aide Saud al-Qahtani was dismissed after overseeing the operation.

The United States imposed economic sanctions on 17 Saudi officials in November for their role in the Khashoggi killing.

The Senate voted in December to move ahead with a resolution to end U.S. military support for the Saudi-led coalition in the war in Yemen, and lawmakers vowed to push for sanctions against the kingdom in the new year.