The United States on Tuesday barred Mohammed al Otaibi, the former Saudi consul general to Istanbul when Saudi journalist Jamal Khashoggi was murdered in the consulate in 2018, from entering the country, the U.S. State Department has announced.

"The murder of Jamal Khashoggi was a heinous, unacceptable crime," the department commented in a statement, adding that it continued to urge the Saudi government to conduct a "full, fair and transparent" trial to hold those responsible for the journalist's death to account.

Khashoggi was a U.S. resident and critic of Saudi Crown Prince M. bin Salman. His killing inside the Saudi consulate caused global outcry, tarnishing the crown prince's image.

The CIA and a number of Western governments have said they believe Prince Bin Salman ordered the killing, a claim Saudi officials deny. Eleven Saudi suspects have been put on trial over the journalist's death in secretive proceedings ongoing in Riyadh.

President Donald Trump has expressed doubts over the CIA's assessment and has argued that Washington must not risk its alliance with Riyadh, the cornerstone of U.S. security policy in the Gulf and regarded as a regional counterweight to Iran.

Otaibi has previously been subject to a U.S. asset freeze over his alleged role in Khashoggi's murder.