In Yemen, Reuters reported that Houthi fighters captured an army base in the city of Taiz.
Residents said a Saudi airstrike hit the installation shortly afterwards.
Saudi-led coalition planes later hit Houthi positions in southern Yemen.
Adel Al-Jubeir, Saudi Ambassador to the US, said coalition forces were ready to stop Houthis from advancing on the port of Aden.
“The Houthis should be under no illusion that we will continue to use force in order to stop them from taking Yemen over by aggressive actions,” said Al-Jubeir.
Hundreds of Houthi supporters rallied in central Sana’a against Saudi Arabia after Riyadh entered a new phase of the conflict focused on political, diplomatic and military action.
The Houthis say they want a return to United Nations peace talks but only after a complete halt to air strikes.