Houthi fighters ride on the back of a truck during a tribal gathering held to mobilize fighters for the battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





Pro-Houthi tribesmen shout slogans during a gathering held to mobilize fighters for battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





Pro-Houthi tribesmen shout slogans during a gathering held to mobilize fighters for battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





Pro-Houthi tribesmen carry their weapons during a gathering held to mobilize fighters for battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





A pro-Houthi tribesman holds an RPG weapon during a gathering held to mobilize fighters for battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





A pro-Houthi tribesman holds the barrel of a machine gun he carries during a gathering held to mobilize fighters for the battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





A pro-Houthi soldier tribesman poses for a photo next to a military armoured personnel during a gathering held to mobilize fighters for battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





Pro-Houthi tribesmen hold up their weapons as they shout slogans during a gathering held to mobilize fighters for the battles against government forces, in Sanaa, Yemen November 24, 2016. (Photo by Khaled Abdullah/Reuters)





Houthi rebels demonstrate skills during a rally held to mobilize fighters for battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





Armed tribesmen loyal to the Houthi movement hold up their weapons during a rally held to mobilize fighters for battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





A Houthi rebel holds the barrel of a machine gun he carries during a rally held to mobilize fighters for battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





Houthi rebels parade during a rally held to mobilise fighters for the battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





A Houthi rebel holds holds an RPG weapon during a rally held to mobilise fighters for the battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





A boy holds his weapon as he sits with armed tribesmen loyal to the Houthi movement riding a truck during a rally held to mobilize fighters for the battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





A boy holds a weapon as he sits with armed tribesmen loyal to the Houthi movement riding a truck during a rally held to mobilize fighters for the battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





Houthi rebels parade during a rally held to mobilize fighters for the battles against government forces, in Sanaa, Yemen December 1, 2016. (Photo by Mohamed al-Sayaghi/Reuters)





Tribesmen attend a gathering held to show support to the new government formed by Yemen's armed Houthi movement and its political allies, in Sanaa, Yemen December 6, 2016. (Photo by Khaled Abdullah/Reuters)





Tribesmen ride in a pick-up during a tribal gathering held to show support to the new government formed by Yemen's armed Houthi movement and its political allies, in Sanaa, Yemen December 6, 2016. (Photo by Khaled Abdullah/Reuters)





Tribesmen attend a gathering held to show support to the new government formed by Yemen's armed Houthi movement and its political allies, in Sanaa, Yemen December 6, 2016. (Photo by Khaled Abdullah/Reuters)





Tribesmen attend a gathering held to show support to the new government formed by Yemen's armed Houthi movement and its political allies, in Sanaa, Yemen December 6, 2016. (Photo by Khaled Abdullah/Reuters)





A tribesman holds a weapon as he attends a gathering held to show support to the new government formed by Yemen's armed Houthi movement and its political allies, in Sanaa, Yemen December 6, 2016. (Photo by Khaled Abdullah/Reuters)





A man carries a part of a missile he says was dropped during a Saudi-led air strike near the northwestern city of Saada, Yemen December 7, 2016. (Photo by Naif Rahma/Reuters)





People pose for a picture next to a part of a missile they say was dropped during a Saudi-led air strike near the northwestern city of Saada, Yemen December 7, 2016. (Photo by Naif Rahma/Reuters)





A supporter of the Houthi movement attends a rally marking the birth anniversary of Prophet Mohammed, in Sanaa, Yemen December 11, 2016. (Photo by Khaled Abdullah/Reuters)





Debris are seen in the al-Saleh mosque after Saudi-led air strikes hit a military post near the mosque in Sanaa, Yemen December 14, 2016. (Photo by Khaled Abdullah/Reuters)





A Muslim Yemeni shows of his coloured face during a gathering marking the birth anniversary of Islam's Prophet Mohammed on December 11, 2016 in the Yemeni capital Sanaa. (Photo by Abdel Rahman Abdallah/AFP Photo)