RABAT—Moroccan Foreign Minister Nasser Bourita on Thursday blamed Spain for the diplomatic spat between the two countries and said mass migrant crossings from Morocco into the Spanish enclave of Ceuta this week were due to the weather and tired border guards. Morocco had appeared to loosen its border controls with Ceuta on Monday as thousands of migrants poured into the enclave, a move widely interpreted as retaliation for Spain’s hosting of a Western Sahara independence leader. Speaking to Reuters, Spanish news agency Efe, and Moroccan news agency MAP in a briefing, Bourita warned that Rabat would take a more assertive stance than in the past, saying “today’s Morocco is not that of the past, and Spain needs to understand this.” Rabat withdrew its ambassador to Madrid this week over Spain’s decision to hospitalise Polisario Front leader Brahim Ghali, letting him into the country with what Morocco said was an Algerian …