Pope Leo has voiced his concerns after several Moroccan migrants died while attempting to cross into the Spanish enclave of Ceuta.
At least 86 people were killed in the rush over the border, which saw around 60,000 migrants enter the territory on Thursday. Spanish authorities believe almost all have now returned.
The death toll is likely to rise in the coming days, as divers search for bodies in the sea.
Speaking during the Angelus prayers in the Vatican on Sunday, Pope Leo made his appeal in Spanish: “I follow with concern the alarming situation in Ceuta, asking God, through the intercession of Our Lady of Africa, that solutions of peace, stability, and justice may be found.”
Pope Leo drew attention to the perilous journeys migrants make in their attempts to enter Spain, during his tour of the country in June. He met migrants in the Canary Islands, which had been a major route from west Africa but is now seeing a decline in boat crossings this year. Conversely, attempted crossings into Ceuta, which borders Morocco on the north coast of Africa, have increased.
Prime Minister Pedro Sanchez described the crossings as “a violation of Spain's territorial integrity”, blaming people smugglers for spreading rumours about a court ruling that migrants could not be deported without due process if they arrive by sea.
Opposition leaders have described it as an “invasion” on Spanish soil. The European Union is set to hold emergency talks this week, after Italy suspended the free border arrangement because of the crisis.