Medical workers have said that the information about the number of casualties is preliminary and that the victims were mostly women.
Some reports indicate that up to 40 people were injured in the crush.
A local journalist said the donor had organised similar handouts before, but this year some 1,000 people arrived, storming an iron barrier under which several women were crushed.
The ministry of the Interior has announced that king Mohammed VI gave his instructions to "bring help and necessary support to the families of the victims and the wounded".
An investigation has been set up to determine what happened and establish responsibility, authorities have said. The king has also made a decision to "take charge personally of the funeral expenses and the funeral expenses of the victims and the care of the wounded", according to the same source. "There was no proper organization during the distribution process, resulting in this disaster", he said.