Spain has deployed troops to Ceuta to patrol the border with Morocco after thousands of migrants swam into the northern African enclave amid heightened diplomatic tensions, Interior Minister Fernando Grande-Marlaska said on Tuesday.

Footage from local Faro TV channel showed soldiers in armoured vehicles guarding the enclave’s beach as dozens of migrants emerged from the water while hundreds of potential migrants stood on the Moroccan side of the fence between the enclave and Morocco.

Soldiers started patrolling the border along with Spanish police, Grande-Marlaska told state broadcaster TVE. As many as 6,000 Moroccans, including about 1,500 minors, swam into Ceuta on Monday and Tuesday, he said.

A spokesman for Ceuta’s government delegation said soldiers will also work with police in sensitive locations within the enclave to maintain order on the streets.

One person died in Monday’s crossing, the spokesman said.

The adult arrivals are being transferred to a local football stadium to be deported back to Morocco. About 1,500 have already been handed back, Grande-Marlaska said.

Minors are being sent to an industrial building.

Ceuta, with a population of 80,000, is an enclave located on the northern tip of Morocco across from Gibraltar.

The Spanish enclaves of Ceuta and nearby Melilla on Morocco’s northern coast have long been a magnet for African migrants trying to reach Europe in search of a better life.

TV channel 24h reported on Tuesday morning that as many as 85 migrants climbed the border fence to break into Melilla, which is located about 300km east of Ceuta.

The arrival of the migrants took place at a time of increased tension between Spain and Morocco over the fate of Brahim Ghali, the leader of the Western Sahara’s Polisario Front, who is in hospital in Spain.

Morocco’s Foreign Ministry issued a strongly worded statement last month deploring what it said was Spain’s decision to admit Ghali under a false identity without informing Morocco, adding that the situation would have repercussions for bilateral relations between the countries.

The United States in December recognised Moroccan sovereignty over the Western Sahara territory, which is also claimed as an independent state by the Polisario Front.

Ghali is hospitalised in Spain, a Spanish diplomatic source told Reuters.

Ghali was accepted into Spain on humanitarian grounds, Spanish Foreign Minister Arancha Gonzalez Laya told Cadena SER radio on Monday evening.