– Pope Francis defended “modern multilateral diplomacy” and international institutions against “the resurgence of nationalistic tendencies” in a major address at the Vatican on Monday.

Francis did not cite specific countries in his speech, delivered to diplomats at the Holy See, but he appeared to be lamenting the mix of jingoism and isolationism that has emerged in the United States and in European nations where populist governments have risen to power.

Noting that the League of Nations, established after World War I, had failed to head off another war largely because countries were not working together, Francis raised the specter of fresh violence.

“The same attitudes are presently threatening the stability of the major international organizations,” he said, urging Europeans in particular to remain united in the face of “temptation to erect new curtains.”

His remarks especially hit a nerve in Italy, where the populist government has cracked down on immigration and denied port entry to vessels that rescue migrants seeking to enter Europe. One such boat, the Sea Watch 3, has been stalled in the Mediterranean awaiting a safe port of call for more than two weeks.

Several Italian bishops and cardinals have urged authorities to allow the migrants to dock in Italy, and many offered to take the migrants into their parishes.

Francis issued his own appeal Sunday, asking European leaders to “show some concrete solidarity” with the migrants. The pope seemed to be adding his voice to a growing chorus of criticism within Italy of the leadership of Interior Minister Matteo Salvini, the hard-line leader of the anti-immigrant League party and the most powerful politician in the country.

In his speech Monday, the pope acknowledged the concerns in Europe and North America about migrants but urged sympathy for them, saying governments should help those fleeing poverty, violence and natural disasters.

“I do not believe that partial solutions can exist for so universal an issue,” he said. “Recent events have shown the need for a common, concerted response by all countries, without exception and with respect for every legitimate aspiration, whether of states or of migrants and refugees themselves.”