The incident was described by sources in the Civil Guard as "very violent" according to Spanish daily El País and news agencies.
Some 500 people are said to have attempted to enter the Spanish territory at 9am on Monday morning.
Armed members of Morocco's security forces are believed to have been stationed in the 'no-man's-land' territory between the Moroccan fence and that of Melilla.
Video: Delegación de Gobierno
The migrants targeted two different sections of the border and were "very violent" as they used "sticks and threw rocks at Spanish and Moroccan police", said a spokeswoman for the Spanish government's representative in Melilla.
About 100 of the roughly 500 migrants involved in the border assault managed to enter Melilla, she added.
It was the latest in a series of coordinated assaults by African migrants on the border of Melilla, which along with fellow Spanish territory Ceuta has the European Union's only land borders with Africa.
The two cities sit across the Mediterranean from mainland Spain, surrounded by Moroccan territory.
On February 17th, about 150 African migrants made it into Melilla in another mass assault by migrants bearing sticks and stones.
Fifteen migrants drowned in Moroccan waters on February 6th while trying to enter Ceuta by sea after several hundred tried to storm the land border.
Spain's interior ministry on Friday posted videos online showing police firing rubber bullets as the migrants swam into Spanish territory from Morocco, but denied this action contributed to the drowning of the migrants.
The spike in the arrival of migrants to Melilla in recent weeks has caused the population of the CETI internment centre in the Spanish outpost to swell.
The centre, which has room for 480 people, currently houses more than 1,000 migrants. Military tents have been set up at the centre to accomodate the overflow.
Depending on treaties between Spain and the country of origin of each immigrant, some are repatriated and others are allowed into Spain.