Houthi Shia militia bombings killed at least 20 civilians on Wednesday in a residential neighbourhood in the southern Yemeni city of Aden, a bastion for forces loyal to exiled President Abd Rabbu Mansour Hadi.
Many of the wounded, including women and children, could not be evacuated from the al-Mansoura neighbourhood due to fighting, medical officials told Efe news agency.
The gravity of the situation has forced authorities to ask citizens for assistance and blood donations.
Both locals and members of the Hadi-loyalist Popular Resistance Committees (PRC) blamed the Houthis for the attack.
Al-Mansoura is a populous district controlled by the PRC, but has been under siege by Houthis rebels.
Meanwhile, officials warned that Houthis were preparing to breach the district.
Aden, the major city in Yemen's south, has been the epicentre of heavy clashes between Houthis and militias loyal to Hadi.