Battle for Yemen

Damage in the building of the Houthi movement's politburo is seen through a broken window of an adjacent house after it was hit by a Saudi-led air strike in Sanaa, Yemen July 7, 2015. REUTERS/Khaled Abdullah

Damage is seen in the building of the Houthi movement's politburo after it was hit by a Saudi-led air strike in Sanaa July 7, 2015. REUTERS/Khaled Abdullah

Medics attend to a fighter of the Popular Resistance Committees after he was injured during clashes with Houthi fighters in Taiz July 7, 2015. REUTERS/Stringer

A poster of Houthi leader Abdul-Malik Badruddin al-Houthi is seen in the house of Brigadier Khaled al-Anduli, an army commander loyal to the Houthi movement, after it was hit by Saudi-led air strikes in Sanaa July 6, 2015. REUTERS/Khaled Abdullah

Guards walk on the rubble of the house of Brigadier Khaled al-Anduli, an army commander loyal to the Houthi movement, after it was hit by Saudi-led air strikes in Sanaa July 6, 2015. REUTERS/Khaled Abdullah

A Houthi follower holds up a rifle as he takes part in a demonstration against the United Nations in Sanaa July 5, 2015. REUTERS/Mohamed al-Sayaghi

Houthi followers take part in a demonstration against the United Nations in Sanaa July 5, 2015. REUTERS/Mohamed al-Sayaghi

Dust rises from the site of a Saudi-led air strike in Taiz July 5, 2015. REUTERS/Stringer

Houthi followers hold mock missiles and their rifles as they shout slogans during a demonstration against the United Nations in Sanaa July 5, 2015. REUTERS/Mohamed al-Sayaghi

People search for survivors under the rubble of the collapsed house of Yemen's late prime minister Faraj Bin Ghanim after it was hit by a Saudi-led air strike in Sanaa July 2, 2015. REUTERS/Khaled Abdullah

A man reacts as he stands next to wreckage at the site of a car bomb attack outside his house in Sanaa June 29, 2015. REUTERS/Khaled Abdullah

Girls wait for food rations outside a charity food assistance center in Sanaa July 1, 2015. REUTERS/Khaled Abdullah

A man looks for survivors under the rubble of the collapsed house of Yemen's late prime minister Faraj Bin Ghanim after a Saudi-led air strike hit it in Sanaa July 2, 2015. REUTERS/Khaled Abdullah

Smoke billows from the site of a Saudi-led air strike in Sanaa July 2, 2015. REUTERS/Khaled Abdullah

Medics attend to a fighter of the Popular Resistance Committees at a hospital after he was injured during clashes with Houthi fighters in Taiz June 27, 2015. REUTERS/Stringer

Police inspect the site of a car bomb attack outside the Qubbat al-Mahdi mosque in Sanaa June 20, 2015. REUTERS/Khaled Abdullah

People display fragment of shells they collected from their house amid clashes between members of the anti-Houthi Popular Resistance Committees and Houthi fighters in Taiz, June 15, 2015. REUTERS/Strin

People look at the rubble of houses destroyed by a Saudi-led air strike in Sanaa June 21, 2015. REUTERS/Khaled Abdullah

A woman sits near her father as he waits to be given a bed at a government hospital in Sanaa June 24, 2015. A country that was already by far the poorest and most unstable on the Arabian Peninsula is now, after three months of conflict, in the grip of a humanitarian disaster. REUTERS/Khaled Abdullah

People walk past houses destroyed by a Saudi-led air strike in Sanaa July 3, 2015. REUTERS/Khaled Abdul