Pope Francis has prayed for an end to the “sacrilegious” war in Ukraine and for the world to show kindness and compassion to refugees as he concluded a two-day visit to Malta that was dominated by his concern for the devastation unleashed by Russia’s invasion.

Though short, the trip has been particularly taxing for the 85-year-old pontiff, who is suffering with strained ligaments in his right knee.

Francis opened his second and final day in Malta by visiting the Grotto of St Paul in Rabat, where the Apostle Paul stayed after being shipwrecked off Malta en route to Rome in AD 60.

According to the biblical account of the period, the Maltese people showed Paul unusual kindness, and he responded by preaching and healing.

Francis has used his visit to Malta to drive home his call for Europe to show the same welcome to migrants and refugees the Maltese showed St Paul.

He expanded that message to express his gratitude for the welcome Europe has shown Ukrainian refugees fleeing the Russian war and his hope the same generosity could be extended to others.

“No one knew their names, their place of birth or their social status; they knew only one thing: that these were people in need of help,” Francis said in a prayer in the grotto.

“Help us to recognise from afar those in need, struggling amidst the waves of the sea, dashed against the reefs of unknown shores.”

Malta has long been at the heart of the European debate over refugee policy.

The country of 500,000 people is frequently criticised by humanitarian aid groups for refusing to let rescue ships dock at its ports.

The government argues it has one of the EU’s highest rates in processing first-time asylum applications relative to the population, and says other, bigger European countries should do more to shoulder the burden.

Upon arriving in Valletta on Saturday, Francis thanked Malta for the welcome it has shown newcomers, and blasted as “sordid” the European Union policy that trains the Libyan coast guard to return smuggled migrants to shore.

Human rights groups have documented gross abuses at the Libyan detention centres where the returned migrants are then housed.

Francis asked for prayers for peace in Ukraine, a day after he blasted Russia’s invasion as “infantile” and based on “anachronistic claims of nationalistic interests”.

He urged the faithful to “think of the humanitarian tragedy unfolding in the martyred Ukraine, which continues to be bombarded in this sacrilegious war.”

The Mass drew an estimated 20,000 people, many of them waving the yellow and white flags of the Holy See and a few Ukrainian ones.

Among them was Alina Shcherbyna, a 25-year-old Ukrainian who arrived in Malta just over a week ago after fleeing her bombed-out home in Dnipro, leaving behind her parents, who are both doctors.

“At school we were studying a lot about the Second World War, about bomb shelters and about this disaster, and we thought it was impossible in present time,” she said.

“We thought it had ended in 1945 and that was it. But now, it’s really shocking for all of us,” she said.