VALLETTA, Malta — Pope Francis said Saturday he was considering a possible visit to the Ukrainian capital of Kyiv and blasted the leader who launched a “savage” war, delivering his most pointed denunciation yet of Russia’s invasion of Ukraine.

In his remarks in Malta, Francis didn’t cite President Vladimir Putin by name, but the reference was clear when he said “some potentate” had unleashed the threat of nuclear war on the world in an “infantile and destructive aggression.”

Pope Francis sits next to Malta’s Archbishop Charles Jude Scicluna aboard a catamaran ferry leaving Valletta’s harbor for Gozo island in Malta on Saturday. Andreas Solaro/pool via AP

“We had thought that invasions of other countries, savage street fighting and atomic threats were grim memories of a distant past,” Francis told Maltese officials on the Mediterranean island nation at the start of a weekend visit.

Francis has to date avoided referring to Russia or Putin by name, in keeping with the Vatican’s tradition of not calling out aggressors to keep open options for dialogue. But Saturday’s criticism of the powerful figure responsible for the war marked a new level of outrage for the pope.

“Once again, some potentate, sadly caught up in anachronistic claims of nationalist interest, is provoking and fomenting conflicts, whereas ordinary people sense the need to build a future that will either be shared or not be at all,” he said.

Francis told reporters en route to Malta that a possible visit to Kyiv was “on the table,” but no dates have been set or trip confirmed. The mayor of the Ukrainian capital had invited Francis on March 8 to come as a messenger of peace along with other religious figures, but has recently warned even healthy city residents who fled that the city is still endangered by Russian hostilities.

Francis also said the war had pained his heart so much that he sometimes forgets about the pain in his knees. Francis has been suffering for months from a strained ligament in his right knee. The inflammation got so bad that the Vatican arranged for a tarmac elevator to get him on and off the plane for Saturday’s flight to Malta, and his limp was more pronounced Saturday.

The Malta visit, originally scheduled for May 2020, was always supposed to focus on migration, given Malta’s role at the heart of Europe’s migration debate. The issue took on more import with the forced exodus of over 4 million Ukrainian refugees. Francis focused his remarks on the perilous Mediterranean migration route and Europe’s flawed migration policies in welcoming people fleeing war, poverty and conflict.

Speaking with Malta’s president by his side, Francis denounced the “sordid agreements” the European Union has made with Libya to turn back migrants and said Europe must show humanity in welcoming them. He called for the Mediterranean to be a “theater of solidarity, not the harbinger of a tragic shipwreck of civilization.”

Francis was referring to the EU’s program to train Libya’s coast guard, which patrols the North African country’s coast for migrant smuggling and brings the would-be refugees back to shore. The program was strongly backed by Italy and other front-line Mediterranean countries to try to stem the flow of hundreds of thousands of desperate migrants each year.

But human rights groups have condemned the EU-funded program as a violation of the migrants’ rights and documented gross abuses in the Libyan detention camps. Just this week, German said its military would no longer provide training to the Libyan coast guard given its “unacceptable,” and in some cases illegal, treatment of migrants.

Francis has condemned the Libyan detention facilities as concentration camps, but he went further Saturday to shame the EU for its complicity in the abuses there.

“Civilized countries cannot approve for their own interest sordid agreements with criminals who enslave other human beings,” he said.

Malta, the European Union’s smallest country with a half-million people, has long been on the front lines of the flow of migrants and refugees across the Mediterranean and often has come under fire for refusing to let rescue ships dock. Just this week a German aid group sought port for 106 migrants rescued at sea and, by Saturday, the ship was heading to Sicily instead.

Malta has frequently called upon its bigger European neighbors to shoulder more of the burden receiving would-be refugees.

Francis has frequently echoed that call, and linked it on Saturday to the welcome the Maltese once gave the Apostle Paul, who according to the biblical account was shipwrecked off Malta around A.D. 60 while en route to Rome and was shown unusual kindness by the islanders.

Later Saturday, Francis traveled by catamaran ferry to the island of Gozo, making his own the Mediterranean seafaring tradition to celebrate a prayer meeting at Malta’s national shrine. Flanked by two Maltese churchmen who are key aides at the Vatican, Francis sat on a white chair on deck for the hourlong trip and was welcomed by thundering canons as the ship came in Gozo’s port.