evidence: The Spanish prime minister on Saturday described a deadly migrant rush on the enclave of Melilla from Morocco as an attack on Spain's "territorial integrity", as human rights activists demanded an investigation. [...] Melilla and Ceuta, Spain's other North African enclave, have the European Union's only land borders on the African continent, making them a magnet for migrants. [...] In the days just before Morocco and Spain patched up their ties, there were several attempted mass crossings of migrants into Melilla, including one involving 2,500 people, the largest such attempt on record. Nearly 500 made it across.