Iran's leader on Thursday condemned as genocide the military intervention by its main regional rival, Saudi Arabia, in Yemen, escalating Tehran's rhetoric against the two-week-old airstrike campaign.

Ayatollah Ali Khamenei said Saudi Arabia would not emerge victorious from the war in Yemen, where Iran-allied Houthi fighters who control the capital Sanaa have been trying to seize the southern city of Aden from local militias.

Iran has repeatedly urged a halt in the airstrikes and called for dialogue in Yemen, but Khamenei's comments are the most critical yet from Tehran about the offensive by Saudi Arabia and its Arab allies.