Residents said the city in southwest Yemen was rocked by explosions and gunfire overnight as the coalition-backed forces of President Abedrabbo Mansour Hadi battled pro-Iranian Huthi Shiite rebels.
Nineteen rebels, four soldiers of a mechanised army unit loyal to the president and four other pro-Hadi fighters were killed, a medical source told AFP.
On Friday, coalition warplanes carried out heavy air strikes on a presidential palace in Taez, Yemen's third largest city, and of positions held by special forces units loyal to former president Ali Abdullah Saleh who has sided with the Huthis.
Residents and security sources said rival fighters clashed Friday night in districts of Aden, while pro-Hadi forces with the support of air strikes held off rebels battling for the past week for control of Aden's refinery, 15 kilometres (nine miles) to the west of the port city.