Suze van Meegen, Sanaa-based protection and advocacy adviser for the Norwegian Refugee Council, said Monday that the violence left aid workers trapped inside their homes and was "completely paralyzing humanitarian operations."
Fighting erupted between and forces loyal to Ali Abdullah Saleh last week, unraveling their fragile alliance, formed in the face of the internationally-recognized government and Saudi-led coalition.
The breakdown of the alliance has led the coalition to step up its bombing of Houthi positions, in support of Saleh's forces.