Many needed medical treatment after scaling the barbed wire fence separating Ceuta from Morocco, with several bleeding from their hands and legs while others were injured falling to the ground.
Those who landed unscathed were triumphant, running through the streets draped in Spanish and EU flags shouting “freedom” before being rounded up by riot police to be taken to detention centres.
It came as a record number of refugees attempt to cross the Mediterranean between Morocco and Spain, with more drowning than ever before following efforts to close the crossing from Turkey to Greece.
Ceuta’s regional government said the incident was the biggest mass border crossing in recent years, with around 700 migrants joining attempts early on Friday morning to scale or break through metal barriers with tools and clubs.
At least 498 people succeeded, with two taken to hospital and 11 Spanish police and 10 members of Morocco’s armed forces injured in clashes near Tarajal.
More than 30 migrants were treated for bone fractures and other injuries, the Red Cross said, while local television footage showed people with blood on their faces and hands, or lying in the road.
The mostly sub-Saharan African migrants are among hundreds stranded in Morocco in attempts to cross the Mediterranean to Europe, or enter Spain via Ceutra and its eastern enclave of Melilla by jumping fences or swimming along the coast.
Many will be returned to their home countries or let go, while others will apply for asylum in Spain and be transferred to the mainland.
At least 55 of Friday’s arrivals were rejected immediately, according to the Civil Guard, because those who are intercepted on the spot can be returned to Morocco in “push back” operations condemned by the United Nations as a violation of international law.
Humanitarian agencies have raised concerns about conditions at the already overcrowded reception centre in Ceuta, where authorities have put military tents in car parks in efforts to house hundreds of asylum seekers.
Maria Vega, from the UN Refugee Agency (UNHCR), said Spanish authorities must properly assess asylum claims before returning people to Morocco and transfer refugees to the mainland as soon as possible.
“These transit centres are above their capacity and they are not an appropriate place for housing refugees, families and victims of trafficking,” she told The Independent.
“Women and children are sleeping in one side, with their husbands and male relatives forced into another place.”
Miss Vega said the poorest and most desperate migrants resort to climbing the fences, while others pay smugglers to board rickety and overcrowded boats from Morocco to Spain across the Strait of Gibraltar.
Refugee crisis - in pictures
Refugee crisis - in pictures
A child looks through the fence at the Moria detention camp for migrants and refugees at the island of Lesbos on May 24, 2016.
Ahmad Zarour, 32, from Syria, reacts after his rescue by MOAS (Migrant Offshore Aid Station) while attempting to reach the Greek island of Agathonisi, Dodecanese, southeastern Agean Sea
Syrian migrants holding life vests gather onto a pebble beach in the Yesil liman district of Canakkale, northwestern Turkey, after being stopped by Turkish police in their attempt to reach the Greek island of Lesbos on 29 January 2016.
Refugees flash the 'V for victory' sign during a demonstration as they block the Greek-Macedonian border
Migrants have been braving sub zero temperatures as they cross the border from Macedonia into Serbia.
A sinking boat is seen behind a Turkish gendarme off the coast of Canakkale's Bademli district on January 30, 2016. At least 33 migrants drowned on January 30 when their boat sank in the Aegean Sea while trying to cross from Turkey to Greece.
A general view of a shelter for migrants inside a hangar of the former Tempelhof airport in Berlin, Germany
Refugees protest behind a fence against restrictions limiting passage at the Greek-Macedonian border, near Gevgelija. Since last week, Macedonia has restricted passage to northern Europe to only Syrians, Iraqis and Afghans who are considered war refugees. All other nationalities are deemed economic migrants and told to turn back. Macedonia has finished building a fence on its frontier with Greece becoming the latest country in Europe to build a border barrier aimed at checking the flow of refugees
A father and his child wait after being caught by Turkish gendarme on 27 January 2016 at Canakkale's Kucukkuyu district
Migrants make hand signals as they arrive into the southern Spanish port of Malaga on 27 January, 2016 after an inflatable boat carrying 55 Africans, seven of them women and six chidren, was rescued by the Spanish coast guard off the Spanish coast.
A refugee holds two children as dozens arrive on an overcrowded boat on the Greek island of Lesbos
A child, covered by emergency blankets, reacts as she arrives, with other refugees and migrants, on the Greek island of Lesbos, At least five migrants including three children, died after four boats sank between Turkey and Greece, as rescue workers searched the sea for dozens more, the Greek coastguard said
Migrants wait under outside the Moria registration camp on the Lesbos. Over 400,000 people have landed on Greek islands from neighbouring Turkey since the beginning of the year
The bodies of Christian refugees are buried separately from Muslim refugees at the Agios Panteleimonas cemetery in Mytilene, Lesbos
Macedonian police officers control a crowd of refugees as they prepare to enter a camp after crossing the Greek border into Macedonia near Gevgelija
A refugee tries to force the entry to a camp as Macedonian police officers control a crowd after crossing the Greek border into Macedonia near Gevgelija
Refugees are seen aboard a Turkish fishing boat as they arrive on the Greek island of Lesbos after crossing a part of the Aegean Sea from the Turkish coast to Lesbos
An elderly woman sings a lullaby to baby on a beach after arriving with other refugees on the Greek island of Lesbos after crossing the Aegean sea from Turkey
A man collapses as refugees make land from an overloaded rubber dinghy after crossing the Aegean see from Turkey, at the island of Lesbos
A girl reacts as refugees arrive by boat on the Greek island of Lesbos after crossing the Aegean sea from Turkey
Refugees make a show of hands as they queue after crossing the Greek border into Macedonia near Gevgelija
People help a wheelchair user board a train with others, heading towards Serbia, at the transit camp for refugees near the southern Macedonian town of Gevgelija
Refugees board a train, after crossing the Greek-Macedonian border, near Gevgelija. Macedonia is a key transit country in the Balkans migration route into the EU, with thousands of asylum seekers - many of them from Syria, Afghanistan, Iraq and Somalia - entering the country every day
An aerial picture shows the "New Jungle" refugee camp where some 3,500 people live while they attempt to enter Britain, near the port of Calais, northern France
A Syrian girl reacts as she helped by a volunteer upon her arrival from Turkey on the Greek island of Lesbos, after having crossed the Aegean Sea
Refugees arrive by boat on the Greek island of Lesbos after crossing the Aegean sea from Turkey
Beds ready for use for migrants and refugees are prepared at a processing center on January 27, 2016 in Passau, Germany. The flow of migrants arriving in Passau has dropped to between 500 and 1,000 per day, down significantly from last November, when in the same region up to 6,000 migrants were arriving daily.
“In 2016 there were around 1,000 people entering through the fences in the entire year,” she added.
“These numbers are not normal and any people are waiting on the other side of the fence trying to reach Europe.”
Security forces frequently prevent anyone of sub-Saharan African appearance approaching Spanish border posts where they can apply for asylum, leading them to cross illegally, Miss Vega said.
Meanwhile, a record 1,200 refugees have reached the Andalusian coast by sea so far this year – a 200 per cent increase on the same period in 2016.
At least 30 people have drowned or gone missing in the past six weeks, including a six-year-old boy found washed up dead on a Spanish beach, almost half of the death toll for the entire last year.
Miss Vega said the UN was concerned about the rocketing death rate, coming after a record year that saw more than 5,000 refugees drown, suffocate or die of hypothermia attempting to reach Europe by sea.
“We appreciate that there are search and rescue actions being taken to save lives by governments and NGOs but what we really need is legal avenues,” she added.
“People should be coming to countries with papers and a visa and not risking their lives, because they have already suffered.
“They’re escaping political, ethnic, religious and gender persecution, bombing and poverty, then they have to suffer another hell trying to reach safety.
“Traffickers and smugglers – those are the ones that are getting money out of this situation.”
Many migrants documented by the UNHCR reaching Spain’s North African enclaves are from sub-Saharan African nations including Nigeria, Guinea and Senegal, although a high number of asylum seekers reaching Melilla are Syrian.
Miss Vega said some families said they journeyed from Libya due to the lawless country’s ongoing civil war and the threat of kidnap and extortion, while news of boats launched from the country sinking may also be driving the trend.
The treacherous crossing between Libya and Italy has become the main refugee route to Europe since the controversial EU-Turkey deal aimed to close the comparatively shorter and safer journey over the Aegean Sea to Greece.
An estimated 100,000 foreign migrants and 250,000 internally displaced people remain in Libya, where a fragile government is failing to stop a bloody competition of control between countless warring militant groups including Isis.
More than 12,300 asylum seekers have reached Europe by sea so far this year, mostly from Syria, Afghanistan, Nigeria, Iraq and Eritrea.