About 700 migrants amassed near the border early Friday before storming the fence, and 498 migrants managed to cross into Spanish territory, the source said.
The others were stopped by the Moroccan military and by Spanish and Moroccan authorities, the source added.
Social media video provided to a local station shortly after the migrants arrived shows many celebrating while running through the streets. Other videos show barefoot and bare-chested migrants shouting "Viva España!" A few migrants had flags of the European Union and Spain draped over their backs. Some could be seen kissing the ground.
Eleven Spanish Civil guards were hurt trying to stop the migrants, the source said. Three had to be taken to a local hospital.
The 498 migrants are receiving assistance from the Spanish Red Cross at a Temporary Migrant Center in Ceuta, the agency said in a statement.
The Red Cross said 18 migrants had to be treated at a local hospital after being hurt while crossing the border.
Desperate attempts to cross
Ceuta, along with the province of Melilla to the east, are Europe's only land borders in Africa. Both enclaves have long been popular transit points for sub-Saharan African migrants trying to cross the sea at the narrow point south of Spain.
At least 800 African migrants tried to storm a border fence into Ceuta from Morocco on New Year's Day, Reuters reported
, citing the Spanish and Moroccan governments.
Most of the migrants that day were prevented from entering Spanish territory. A handful of migrants scaled the 6-meter-high barbed-wire fence but were eventually removed by cranes, Reuters reported.
Dozens of Moroccan security agents were injured in the incident, along with five Spanish police officers.
A young woman was arrested in December 2016 after being caught trying to smuggle a 19-year-old African migrant into Ceuta in her suitcase
. The man was treated for lack of sufficient oxygen inside the compact travel bag, Spain's Civil Guard said in a statement.
This creative but dangerous method of concealment is one of several desperate approaches to illegal smuggling that the Spanish Civil Guard has faced on the Ceuta border.
Two migrants -- a man and a woman -- from Guinea were also rescued in December after authorities discovered them hidden inside the dashboard and the backseat of a Volkswagen Golf, the Spanish Civil Guard said. A Moroccan man driving the car, which had been stolen, was arrested, officials said.