Almost 600 migrants tried to enter Europe by storming border fences separating Spain's North African enclave of Ceuta from Morocco on Thursday, emergency services said.
The Spanish Red Cross said in a tweet it was called to check on 592 people after the massive assault shortly after dawn. The Red Cross said 132 migrants were hurt as they scaled the high, barbed-wire fences and 11 were taken to hospital for treatment.
It said 22 police officers were also hurt and four of them were hospitalized.
The Spanish government did not immediately say how many migrants made it onto Spanish soil.
As the migrants scaled the fences, they threw feces and quicklime, a skin irritant, at police officers trying to hold them back, Spanish news agency Europa Press reported, citing unidentified police sources and emergency crews.
A spokesman for the Guardia Civil police force in Ceuta told AFP the migrants managed to climb over the double barrier, which is covered in small blades, early on Thursday morning.
They scrambled over "all of a sudden, with much violence," and some attacked police with quicklime they had in tubes and bottles.
As a result, "more than a dozen police" were injured, four of whom had to go to hospital for burns in the face and arms.
Isabel Brasero, spokeswoman for the Red Cross, said they had to attend to 30 migrants with injuries, none serious.
Eleven of them were taken to hospital for stitches and possible fractures, she added.
Sub-Saharan Africans living illegally in Morocco try to get to Europe each year by climbing rows of 6-meter (20-feet) high fences surrounding Ceuta and Melilla, Spain's other North African enclave. Those who make it across head for crowded, temporary migrant accommodation centers. They are eventually repatriated or let go.
Some Moroccans and North Africans try to illegally enter the territories hidden in a variety of inhumane ways. In 2015, a 27-year-old Moroccan man suffocated to death while hiding inside a suitcase in the trunk of a car. In the same year, an eight-year-old boy from the Ivory Coast was found curled up inside a suitcase without ventilation.
Thursday's mass charge added to pressure on Spanish authorities from a recent wave of migration, mostly migrants crossing the Mediterranean on unsafe boats.
The International Organization for Migration says so far this year more than 22,700 migrants have arrived in Spain — three times more than in the same period last year.
Almost 20,000 of them arrived by sea, as good weather allowed more crossings on the short route across the Strait of Gibraltar and a recent crackdown by Libyan authorities had led migrants to choose other routes.
Last week, two vessels of a Spanish NGO involved in rescuing migrants in the Mediterranean arrived in the Spanish port of Palma on Saturday carrying a woman found drifting on a deflated dinghy off Libya as well as the bodies of a boy and another woman.
The rescued woman was a 40-year-old from Cameroon named Josepha. Proactiva said it transported her to Spain – where the Spanish Red Cross received her – for her "protection" and to enable her to testify freely.
Proactiva Open Arms accused Libyan coastguards of having saved the rest of the migrants on board the dinghy but not the two women and the child, whom they say refused to board the rescue vessel and go back to Libya.
The two ships of Proactiva Open Arms were escorted to the port of the capital of the Balearic island of Majorca by a Spanish police ship.