Labourers stack dried bricks inside a kiln, where they will be fired, at a brick factory on the outskirt of Sanaa, Yemen, June 1, 2016. Traditional mud brick tower houses have always been a source of pride to Yemenis, and over a year into a devastating civil war, they are also providing some much-needed jobs in the ancient capital Sanaa. (Photo by Mohamed al-Sayaghi/Reuters)

People gather at the site of a bomb explosion in Sanaa December 23, 2014. Five bombs exploded on Tuesday in Sanaa's old quarter, where many supporters of the Shi'ite Muslim Houthi group live, killing at least one person and wounding another, a Yemeni security official said. No one has claimed responsibility for the attacks, but the Houthis have been fighting the Sunni Islamist militant al Qaeda group and allied tribesmen since its gunmen captured Sanaa in September and forced the resignation of a government they had long seen as corrupt. (Photo by Khaled Abdullah/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)

Women loyal to the Houthi movement parade to show support to the movement in Sanaa, Yemen January 17, 2017. (Photo by Khaled Abdullah/Reuters)

A man sleeps on a wheelbarrow outside a closed shop at a market during the first day of a ceasefire in Yemen's capital Sanaa April 11, 2016. (Photo by Khaled Abdullah/Reuters)

A homeless man rests on the side of a street at the old quarter of Yemen's capital Sanaa November 27, 2015. (Photo by Khaled Abdullah/Reuters)

Children ride in the trunk of a car on a flooded street in Sanaa, Yemen August 1, 2016. (Photo by Khaled Abdullah/Reuters)