Dozens of sub-Saharan African migrants forced their way this morning over a barbed-wire fence into Spain's North African enclave of Ceuta, which borders Morocco.
Television footage showed migrants perched on the top of the fence as they tried to get over. Several people were injured after storming the barrier, emergency services said.
Between 150 and 200 people crossed into Spain, Spanish media reported.
The government did not immediately respond to a request for comment or confirm the number of migrants who crossed the border. Their legal status in Spain has yet to be determined.
"Most of the people have been apprehended and we are looking for the rest so that they can immediately be processed," Juan Ignacio Zoido, Spain's interior minister, told reporters as he arrived in Brussels, adding that 20 per cent of those who had stormed the border had not yet been found.
Spain's two enclaves in Morocco, Ceuta and Melilla, are often used as entry points into Europe for African migrants, who either climb over their border fences or attempt a dangerous swim along the coastline.
Some also try to cross from Morocco into mainland southern Spain by boat, despite tighter controls in recent years by the two countries which has diminished the number of those attempting this route.
Four African migrants drowned and 34 were rescued on Wednesday off the coast of Morocco when their boat sank, though it was unclear whether they were heading to Spain or to one of the two Spanish North African enclaves.
Libya has become a more common departure point for African migrants, most from sub-Saharan countries, who attempt the crossing to Italy.
An estimated 4,663 migrants have died in the Mediterranean this year, while a record number of migrants – 171,299 as of 28 November – have reached Italy by boat from North Africa in 2016.