The death toll in an attempt by hundreds of migrants to break through a border fence between Morocco and a Spanish exclave earlier this week has risen to 23, Moroccan state television reported on Sunday.

On Friday, Rabat said 18 migrants had died, while others and security forces were injured, during a mass attempt to storm the border to the Spanish exclave of Melilla.

Five further migrants have since died, raising the toll to 23, state television reported late on Saturday, citing unnamed local sources.

The 18 injured migrants and one member of security forces are still under medical observation, the broadcaster added without elaborating.

The independent Moroccan Association of Human Rights accused the security forces of using "unjustified" violence against the migrants and mistreating them.

Amin Abidar, the group’s head in the city of Nador near the border with Melilla, told dpa that migrants had been left trapped on the ground for hours without medical assistance.

For its part, Morocco's Interior Ministry accused the migrants of using violence.

Morocco became independent from France and Spain in 1956. Nevertheless, Spain still holds two autonomous cities there: Melilla and Ceuta, 250 kilometers (155 miles) further west on the Strait of Gibraltar. Both are claimed by Rabat.

Near the two cities, tens of thousands of people, mainly from sub-Saharan Africa, often wait for a chance to enter the European Union.

Usually, several hundred people at a time try to surprise the border officials and get across the border en masse.