As the Saudis and the Americans tried to put the crisis behind them,
the brutality described in the leaks served as a reminder of why Mr. Khashoggi’s disappearance has triggered an international backlash more (severe)than countless mass killings or rights violations.
https://www.nytimes.com/2018/10/17/world/europe/turkey-saudi-khashoggi-dismember.html?action=click&;module=Top%20Stories&pgtype=Homepage
severe→severelyでしょうか？