SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the portraits of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners bury the corpse of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the portraits of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the coffin of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the portraits of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the coffin of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the portraits of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the portraits of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)

SANAA, YEMEN - NOVEMBER 04: Yemeni mourners carry the portraits of renowned politician Mohammed Abdulmalik al-Mutawakkil, secretary general of the Union of Popular Forces Party, one of the parties allied to the Shiite Houthi movement, during his funeral in Sanaa, Yemen on November 04, 2014. Mutawakkil, a political thinker and a Yemeni university professor, was assassinated by unknown gunmen on a motorbike in a street of the capital on November 02, 2014. (Mohammed Hamoud - Anadolu Agency)