Trump defence chief Mattis says Khashoggi murder threat to 'regional stability'

Mattis did not mention Saudi Arabia directly in connection with the 2 October killing of Khashoggi at the kingdom's consulate in Istanbul, Turkey.

But he noted that US Secretary of State Mike Pompeo revoked visas of Saudis implicated in the killing of the Washington Post writer, and he said additional measures will be taken.

Turkish officials have said that a Saudi team of 15 men tortured, killed and dismembered the writer and in a premeditated act.

After weeks of lies and denials, Riyadh eventually admitted he was killed at the consulate and that the killing was premeditated.

Mattis made no move to directly blame Saudi and did not refer to the calls from members of Congress to cut arms sales to Saudi Arabia or impose sanctions on the kingdom.

But his broader mention of the matter toward the end of his speech underscores the serious national security ramifications the incident poses for relations with a key US ally.

"With our collective interests in peace and unwavering respect for human rights in mind, the murder of Jamal Khashoggi in a diplomatic facility must concern us all greatly," Mattis told international officials and experts at the Manama Dialogue.

"Failure of any one nation to adhere to international norms and the rule of law undermines regional stability at a time when it is needed most."

He added that he will continue to consult with US President Donald Trump and Pompeo as they consider the broader implications of the matter.

Saudi Foreign Minister Adel Jubeir, who spoke after Mattis at the conference, said hysterical media are rushing to judgment in the Khashoggi case.

"Unfortunately there has been this hysteria in the media about Saudi Arabia's guilt before the investigation is completed," he said, in response to questions about the killing. "What we say to people is wait until everything is done" then decide if the investigation was serious or not.

Saudi Arabia's slow shift to reveal more details about the killing of Khashoggi reflects the kingdom's acknowledgement that the killing could have a serious diplomatic, and possibly economic impact.

Khashoggi lived in self-imposed exile in the US for the past year and wrote editorial columns for The Washington Post that were critical of Saudi Crown Prince Mohammed bin Salman, the kingdom's heir apparent.