Incidents verified by the U.N. included seven air strikes that hit a prison in the Shaub district of Sanaa.
Yemeni forces launched a Scud missile at a missile base in Saudi Arabia on Tuesday, Yemeni state news agency Saba quoted the military's spokesman as saying.
Jamal Benomar, the UN envoy to Yemen, has described Saudi military action as an “Iraq-Libya-Syria scenario”.
Pakistan is considering a request from Saudi Arabia for troops to send to Yemen, the foreign office said on Thursday, Reuters reports.