Defense Secretary James Mattis on Saturday condemned the killing of Washington Post columnist Jamal Khashoggi, warning that his slaying threatened to undermine stability in the Mideast.

Mattis renewed President Trump Donald John TrumpBiden says voters should choose who nominates Supreme Court justice Trump, Biden will not shake hands at first debate due to COVID-19 Pelosi: Trump Supreme Court pick 'threatens' Affordable Care Act MORE's vow to uncover the full details of the events that led to Khashoggi's killing, adding that the U.S. would take unspecified additional measures against those found to be responsible, Reuters reported.

“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 said during a conference in Bahrain, according to the news outlet.

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“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.

The outlet noted that Mattis did not mention Saudi Crown Prince Mohammed bin Salman by name during his address, nor did he announce any change in U.S. arms sales policy to Riyadh, which some lawmakers have begun to issue calls for. Some in Congress have accused the crown prince of orchestrating the operation that killed Khashoggi.

Mattis's comments come days after Saudi officials first acknowledged Khashoggi's death, saying he was inadvertently killed during a dispute with officials inside the Saudi consulate in Istanbul. The dissident journalist had been missing since Oct. 2, when he was last seen entering the facility.

The kingdom's top prosecutor announced Thursday that Khashoggi was killed in a "premeditated" murder.

Trump is facing pressure from lawmakers and Turkey to punish the kingdom for Khashoggi's slaying. His administration has revoked visas for officials identified by the Saudis as connected to the journalist's death, and has said it is weighing sanctions under the Global Magnitsky Act designed to punish human rights violators.

Trump has repeated Crown Prince Mohammed and King Salman's claims that they had no knowledge of the operation, while voicing reluctance to cancel or suspend arms deals with the Saudis, arguing that such moves could cost U.S. companies billions of dollars and many lost jobs.

Trump was briefed Thursday by CIA Director Gina Haspel on the investigation into Khashoggi's death.