Houthi political leader Saleh al-Samad reported killed in Yemen
Samad is the highest ranking Houthi figure to be killed by the Saudi-led coalition to date.
His death will come as a blow to the Zaydi-Shia rebel group who took over the capital Sanaa in September 2014, forcing the government south.
A Saudi-led coalition entered the war in March 2015 on the side of government.
At the beginning of April, Samad dubbed 2018 "the year of ballistic excellence", referring to missiles the rebels have fired across the border.
Since November, the Houthis have launched several ballistic missiles at neighbouring Saudi Arabia, which have been intercepted by anti-aircraft defence.
The Houthi's supreme leader Abdel Malek al-Houthi made a statement on the group's al-Masirah channel, saying that Saudi Arabia and the US will be held responsible for what he called the "heinous crime" of Samad's death.
He also condemned the Saudi-led coalition airstrike on Sunday that killed scores of people gathered to celebrate a wedding in nothern Yemen's Hajja province.
He said that the attacks would strengthen the communities, and that the "martyrs" would not be forgotten and their families honoured.
Houthi rarely makes public appearances.
Mahadi al-Mashat has been named as the successor to the political leadership of the rebel group.
Mashat is a representative of Houthi leader Abdul Malek al-Houthi.