U.S. Defense Secretary Jim Mattis has warned of “additional measures” in response to the killing of journalist Jamal Khashoggi, directing rare criticism against Saudi leaders late Friday. Speaking at a security conference in Bahrain attended by several top Saudi officials, Mattis said Khashoggi’s killing in the Saudi consulate in Istanbul was more than just a human rights issue. “Failure of any nation to adhere to international norms and the rule of law undermines regional stability at a time when it is needed most,” he said. While Mattis did not directly accuse the Saudi leadership of involvement in Khashoggi’s killing and stressed the Trump administration’s “undiminished” respect for the Saudi people, he added that “with our respect must come transparency and trust.” Saudi Arabian Foreign Minister Adel al-Jubeir, who spoke after Mattis at the conference, lamented that the response to Khashoggi’s murder “has become fairly hysterical.” “I think people have assigned blame on Saudi Arabia with such certainty before the investigation is complete,” he said. Saudi authorities initially claimed Khashoggi was killed after a fight in the consulate spiraled out of control. They admitted earlier this week, however, that Khashoggi was murdered in a “premeditated” operation by Saudi operatives who they say took matters into their own hands.