Russia will be the elephant in the room as Pope Francis begins a four-day visit to the Baltics amid renewed alarm about Moscow's intentions in the region it has twice occupied.

Francis is travelling to Lithuania, Latvia and Estonia to mark the 100th anniversaries of their independence and to encourage the faith in the nations, which saw five decades of Soviet-imposed religious repression and state-sponsored atheism.

"Fifty years of occupation left their mark both on the church and on the people," said Monsignor Gintaras Grusas, archbishop of Vilnius. "People have deep wounds from that period that take time to heal."

Pope Francis waves to journalists as he boards his airplane on the occasion of his trip to Lithuania, Latvia and Estonia at Rome's Fiumicino International Airport, Saturday, Sept.22, 2018. Pope Francis heads to Europe's northeastern peripheries this weekend to celebrate the faith in three Baltic countries amid renewed alarm about Russia's intentions in the region it twice occupied. (AP PhotoAlessandra Tarantino)

Pope Francis waves to journalists as he boards his airplane on the occasion of his trip to Lithuania, Latvia and Estonia at Rome's Fiumicino International Airport, Saturday, Sept.22, 2018. Pope Francis heads to Europe's northeastern peripheries this weekend to celebrate the faith in three Baltic countries amid renewed alarm about Russia's intentions in the region it twice occupied. (AP PhotoAlessandra Tarantino)

Francis lands Saturday in the Lithuanian capital Vilnius to begin four-day, three-country trip that will feature encounters with political leaders as well as the Catholic, Lutheran and Russian Orthodox faithful.

Pope Francis boards his airplane on the occasion of his trip to Lithuania, Latvia and Estonia at Rome's Fiumicino International Airport, Saturday, Sept.22, 2018. Pope Francis heads to Europe's northeastern peripheries this weekend to celebrate the faith in three Baltic countries amid renewed alarm about Russia's intentions in the region it twice occupied. (AP PhotoAlessandra Tarantino)

Pope Francis boards his airplane on the occasion of his trip to Lithuania, Latvia and Estonia at Rome's Fiumicino International Airport, Saturday, Sept.22, 2018. Pope Francis heads to Europe's northeastern peripheries this weekend to celebrate the faith in three Baltic countries amid renewed alarm about Russia's intentions in the region it twice occupied. (AP PhotoAlessandra Tarantino)