At least 22 people were killed on Wednesday in tank and mortar shelling by rebel forces on residential areas in Yemen's second city Aden, a medic and a local official said.

"Twenty-two dead and more than 70 wounded have been transferred to several hospitals in Aden," a medical official told AFP, adding that most of the casualties were civilians.

A local official confirmed that rebel forces "randomly shelled... civilian homes" Mualla and Crater districts of Aden.