MADRID (AP) -- Spain deployed its military to the Moroccan border Tuesday as thousands of Moroccans walked or swam onto European soil for the second day in a row after Rabat loosened border controls in a diplomatic spat.

Live footage on Spain's public broadcaster TVE showed dramatic scenes of soldiers carrying children in their arms and Red Cross personnel helping migrants who were emerging from the water shivering and exhausted. One unconscious woman laid on the sand before she was carried away on a stretcher.

The sudden influx of migrants has deepened the diplomatic spat between Rabat and Madrid and created a humanitarian crisis for Ceuta, the Spanish city of 85,000 that lies in North Africa on the Mediterranean Sea, separated from Morocco by a double-wide, 10-meter (32-feet) fence.

Prime Minister Pedro Sanchez canceled a trip to Paris, where he was to attend a summit on international aid to Africa, to focus on the crisis with Morocco.

By Tuesday morning, at least 6,000 sea-soaked people had crossed the border into Ceuta since the first arrivals began early Monday, the Spanish government said, including 1,500 thought to be teenagers. The number getting in slowed but didn't stop Tuesday as Spain deployed additional police and soldiers to the border.

Some 2,700 adults were already returned to Morocco from the latest surge, according to Spain's Interior Ministry. Morocco and Spain signed an agreement three decades ago to return all those who swim across the border.

By Tuesday afternoon, Moroccan authorities closed the road leading to the border post with Ceuta and anti-riot police dispersed crowds of would-be migrants. Neither the government in Rabat nor local officials have commented about the mass influx or responded to queries by The Associated Press.

“It's such a strong invasion that we are not able to calculate the number of people that have entered,'' said Juan Jesus Vivas, the president of Ceuta, an autonomous city of about 20 square kilometers (7.7 square miles).

“The army is in the border in a deterrent role, but there are great quantities of people on the Moroccan side waiting to enter,'' he told Cadena SER radio.

One young man drowned and dozens were treated for hypothermia. The arriving adults were being transferred to Ceuta's main soccer stadium as they waited to be returned to Morocco while those thought to be minors were sent to warehouses run by the Red Cross and other groups.

Several Spanish armored vehicles parked Tuesday at Tarajal beach in Ceuta, where the border fence leads to a short breakwater.

In a video shared by a Spanish police union urging authorities to send in more reinforcements, anti-riot officers behind the border fence were using shields to protect themselves from stones being thrown by people in Morocco.

Interior Minister Fernando Grande-Marlaska denied local media reports saying that unaccompanied migrants under 18, who are allowed to remain legally under the tutelage of Spanish authorities, were being deported.

The European Union's top migration official - Home Affairs Commissioner Ylva Johansson - described the incidents as “worrying,'' and she called on Morocco to prevent people from setting out in the first place.

“The most important thing now is that Morocco continues to commit to prevent irregular departures, and that those who do not have the right to stay are orderly and effectively returned,'' Johansson told members of the European Parliament.

“Spanish borders are European borders. The European Union wants to build a relationship with Morocco based on trust and shared commitments. Migration is a key element in this,'' she said.

Morocco's loosened border watch came after Spain decided to give a visa for medical treatment to the chief of a militant group that fights for the independence of Western Sahara. Morocco annexed the sprawling region on the west coast of Africa in 1975.

Morocco's Foreign Ministry has said Madrid's move to assist Brahim Ghali, head of the Polisario Front that has fought Morocco, was “inconsistent with the spirit of partnership and good neighborliness'' and vowed there would be “consequences.''

Vivas, Ceuta's conservative regional president, said residents were in a state of “anguish, concern and fear” and 60% of the city's children had not shown up for school on Tuesday. He also linked the sudden mass arrival to Spain's compassionate assistance to Ghali.

The Spanish government itself, however, officially rejects the notion that Morocco is punishing Spain for a humanitarian move.

“I cannot envisage that putting the lives of young people and minors at risk is in response to a humanitarian issue, I simply cannot conceive it,'' Foreign Minister Arancha Gonzalez Laya said.

The prime minister's office said the government was supporting residents in Ceuta “to ensure their safety and guarantee public order.”

“My priority at this time is to restore normalcy in Ceuta,'' Sanchez wrote in a tweet. “Its citizens must know that they have the absolute support of the government of Spain and the utmost firmness to ensure their safety and defend their integrity as part of the country.''

Sanchez was also facing a political storm at home, with the far-right Vox party blaming the migration crisis on the government's “inaction” and sending its leader on a quick visit to Ceuta.

Many African migrants regard Ceuta and nearby Melilla, another Spanish territory, as a gateway into Europe. In 2020, 2,228 chose to cross into the two enclaves by sea or land, often risking injuries or death. The year before the figure hit 7,899.

On Tuesday, another 80 African migrants also crossed into Melilla, 350 kilometers (218 miles) east of Ceuta, by jumping over the enclave's double fence.

Morocco scored a diplomatic victory last year when the previous US administration under Donald Trump recognized Rabat's sovereignty over the disputed Western Sahara to pave the way for normalizing relations between Israel and Morocco.