The U.S. Geological Survey measured the earthquake at 6.5 on the open-ended Richter scale, while European agencies put it at 6.1 to 6.3, the BBC reported.
The earthquake -- Morroco's worst in more than 40 years -- struck at about 2:28 a.m. local time, shaking the Strait of Gibraltar, just off the northern coast of Morocco, Aljazeera reported.
While the Al Hoceima area seemed to have escaped major damage, injured people have been pouring into the city from neighboring villages where most live in mud-brick buildings not designed to withstand earthquakes.
Rescue efforts in the area were overwhelmed and the Red Cross/Red Crescent in Tunis said it sent 200 relief workers into the area. Morocco's King Mohammed VI has sent military personnel to assist in rescue efforts.
Mayor Mohammed Boudra said most of the dead were women and children, since most of the men of the area mainly work overseas.