Saudi-led coalition planes have targeted Houthi strongholds with greater intensity since a Houthi-led attacked killed dozens of Arab coalition forces last Friday.
Yemen is torn between the Houthis, allied with army units that have pledged allegiance to Saleh, and forces loyal to exiled President Abed Rabbo Mansour Hadi.
The conflict has killed over 2,100 civilians, according to the United Nations.
