JON NAZCA and MARIANO VALLADOLID 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 yesterday, 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 some 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…