Migrants were still trying to cross from Morocco into the Spanish enclave of Ceuta on Wednesday after a record 8,000 people poured over the border this week, escalating tensions between Rabat and Madrid.
Some tried to swim across to beaches patrolled by police after the unprecedented wave of arrivals earlier this week.
Spain's Prime Minister Pedro Sanchez has vowed to "restore order" in Ceuta, and on Wednesday accused Morocco of "disrespect" after the influx.
Some 5,600 migrants had already been sent back, Madrid said, but that did not stop more from trying to make the risky crossing Wednesday
A handful of people, mostly Moroccan, swam to reach the Spanish side, their slow progress carefully watched by dozens of soldiers deployed along the beach with riot shields and batons, according to a reporter at the scene.
It was not clear how many managed to cross, but the flow had slowed to a trickle.
Those who did make it to shore were immediately picked up by soldiers and escorted to medics offering help, although few appeared to need it.
They were then frog-marched back to the border fence and sent home.
Near the border fence, hundreds of people had massed on the neighbouring Moroccan beach, but the crowd was broken up and turned back to the town of Fnideq.
At one point Moroccan security tried to block people from entering the water while Spanish police fired tear gas to deter migrants from swimming to Ceuta.
Many cited desperate living conditions in Morocco for making the arduous crossing to Ceuta.
Spanish security forces throw tear gas at Moroccan and sub-saharan migrants attempting to cross the fence of the Spanish enclave of Ceuta. Source: AP Photo/Mosa'ab Elshamy
"You have a family and you have seven euros to feed 8 people, what do you do?" said 34-year-old Mohammed Tribak who swam over on Monday.
'Protecting Europe's borders'
The influx comes against the backdrop of increased tensions with Morocco over Spain's decision to provide medical treatment for the leader of the Polisario Front. The head of the Western Sahara independence movement has been seriously ill with COVID-19.
The row revived the issue of migration into the EU, but the Vice President of the European Commission, Margaritis Schinas, said Wednesday the continent "won't be intimidated by anyone".
But Europe would "not be a victim of these tactics", he added.
"Ceuta is Europe, this border is a European border and what happens there is not a problem for Madrid, but a problem for all" Europeans.
France's Europe Minister Clement Beaune said Paris supported Spain because "protecting Spain's borders is protecting Europe's borders".
The record numbers of migrant arrivals have sent diplomatic tensions soaring between Madrid and Rabat, prompting fighting words from Mr Sanchez on Wednesday.
"This is an act of defiance," he told parliament, a day after visiting Ceuta.
"The lack of border control by Morocco is not a show of disrespect of Spain, but rather of the European Union."
'Steep price'
Analysts said it was clear Morocco had turned a blind eye to the human tide surging into Ceuta to put diplomatic pressure on Spain to recognise its sovereignty over Western Sahara.
Most of the migrants crossed into Ceuta largely unimpeded by Moroccan security forces on Monday, but by Tuesday morning, Rabat had deployed reinforcements at the Fnideq border crossing.
To reach Ceuta, they swam or simply walked at low tide from Moroccan beaches a few kilometres to the south. Some used inflatable swimming rings and rubber dinghies.
But one man drowned making the attempt, Spanish officials said.
The crisis comes after Madrid allowed Polisario Front leader Brahim Ghali to fly to northern Spain in mid-April to be treated for COVID-19, angering Rabat.
A Spanish army soldier helps a young migrant from Morocco on his arrival in Ceuta, Spain. Source: Antonio Sempere/Europa Press via Getty Images
The Front has fought for the independence of Western Sahara, a former Spanish colony mainly under Moroccan control.
Morocco's minister of state for human rights, Mustapha Ramid, said Wednesday it was "clear" Spain had favoured its ties with the Polisario and Algeria over those with Morocco by hosting Ghali.
"Spain must also know that the price for discrediting Morocco is steep," he added in a Facebook post.
Morocco's authorities have long wanted Spain to acknowledge their authority over Western Sahara, as Washington did in December under former president Donald Trump.
Spain maintains that a solution to the issue can only come from a United Nations-brokered agreement.
During a radio interview on Wednesday, Spanish Foreign Minister Arancha Gonzalez Laya said Madrid "could not" change its position because Spain "respects international law".
