A sudden influx of migrants swimming into the Spanish enclave of Ceuta in northern Africa is a serious crisis for Europe, Prime Minister Pedro Sanchez said on Tuesday, vowing to re-establish order promptly amid heightened diplomatic tensions with Morocco. Spain deployed troops to Ceuta to patrol the border with Morocco after around 8,000 migrants, many from Sub-Saharan Africa and including 1,500 minors, entered the enclave on Monday and Tuesday by swimming in or climbing over the fence. Armoured vehicles were guarding Ceuta"s beach on Tuesday, and soldiers and police used batons to clear migrants from the beach and threw smoke bombs to discourage others from crossing. A Reuters reporter on the ground said the number of arrivals by sea had slowed, and some migrants were voluntarily returning to Morocco. A few others could be seen being carried away by soldiers. Footage of the beach at around 8 p.m. local time showed nearly all migrants had been cleared. Spain said approximately 4,000 migrants had already been sent back to Morocco, under a readmission deal. The regional leader of Ceuta criticised what he described as Morocco"s passivity in the face of Monday"s surge, and some independent experts said Rabat had initially allowed it as a means of pressuring Madrid over its decision to admit a rebel leader from the Western Sahara to a Spanish hospital. The Spanish government did not make that connection, with Sanchez calling the north African nation a friend of Spain and the interior ministry citing cooperation over the readmissions, although Foreign Minister Arancha Gonzalez Laya told Morocco"s ambassador Spain rejected and disapproved of the mass arrivals. Rabat recalled its ambassador to Madrid for consultations, said a diplomatic source who declined to be named, adding that relations with Spain needed a moment of "contemplation". Moroccan authorities did not respond to requests for comment. Moroccan citizens stand next to and swim around the fence between the Spanish-Moroccan border, after thousands of migrants swam across this border on Monday, in Ceuta, Spain, May 18, 2021. REUTERS/Jon Nazca Spanish legionnaires stand around Moroccan citizens as they lie down on El Tarajal beach, next to the fence between the Spanish-Moroccan border, after thousands of Moroccans swam across this border on Monday, in Ceuta, Spain, May 18, 2021. REUTERS/Jon Nazca Spanish legionnaires stand around Moroccan citizens, after thousands of Moroccans swam across Spanish-Moroccan border on Monday, in Ceuta, Spain, May 18, 2021. REUTERS/Jon Nazca 1/7 Spanish legionnaires stand around Moroccan citizens as they lie down on El Tarajal beach, next to the fence between the Spanish-Moroccan border, after thousands of Moroccans swam across this border on Monday, in Ceuta, Spain, May 18, 2021. REUTERS/Jon Nazca Moroccan TV footage showed authorities setting up barriers on Tuesday afternoon to prevent people from crossing into Ceuta, but footage filmed from the Spanish sideearlier showed a Moroccan soldier or policeman wavingdozens of running migrants through a gate to no-man"s land without any checks. "This sudden arrival of irregular migrants is a serious crisis for Spain and Europe," Sanchez said in a televised address before his arrival in Ceuta. European Commission Vice-President Margaritis Schinas tweeted that the enclave"s frontier was a European border, expressing his "full solidarity with Spain". Ceuta, with a population of 80,000, is on the northern tip of Morocco across from Gibraltar. Along with another Spanish enclave, Melilla, it has long been a magnet for African migrants seeking a better life in Europe. Morocco has a claim on both. WESTERN SAHARA DISPUTE The spike in arrivals took place after Rabat expressed its anger last month when Spain discreetly admitted Brahim Ghali, the leader of Western Sahara"s rebel Polisario Front to hospital. Madrid said it acted on purely humanitarian grounds. read more Morocco"s Foreign Ministry criticised what it said was Spain"s decision to admit Ghali under a false identity without informing Morocco, warning of repercussions. The Polisario Front wants the Western Sahara to be an independent state rather than part of Morocco. Algeria, Morocco"s regional rival, backs the Polisario Front. The United States in December recognised Moroccan sovereignty over the Western Sahara territory.