“We think they could say something more about concern on territorial integrity, those type of issues,” U.S. ambassador to the Holy See, Kenneth F. Hackett, told journalists in Rome ahead of Putin’s arrival.

Hackett described the conflict in eastern Ukraine as one of the “issues of great concern,” and said the Vatican should increase its diplomatic efforts with Russia: “Maybe this is an opportunity where the Holy Father privately can raise those concerns.”
Putin’s meeting with the Pope follows a warning from G7 leaders that Russia could face further sanctions over Ukraine if Moscow fails to uphold a peace agreement signed in February.

The Russian president has repeatedly denied taking an active role in violence in Ukraine, a claim Hackett said contradicted intelligence.

“It does seem that Russia is supporting the insurgents and it does seem that there are Russian troops inside Ukraine. This is a very serious situation.”

The ambassador’s position reflects that of U.S. President Barack Obama, who has adopted a firm stance with Putin while another G7 leader, Italian Prime Minister Matteo Renzi, opted instead to welcome the Russian president to Milan. Canadian Prime Minister Stephen Harper has also taken a firm stance on Putin and Russia.

Following a tour of Milan’s Expo world fair, Putin will travel to Rome for his second meeting with the Pope. The two leaders first met in November 2013 and discussed instability in Ukraine, although before Russia last year annexed Crimea Peninsula.

Francis has previously called for a peaceful resolution in Ukraine, although the pontiff has come under criticism for not specifically addressing Moscow’s involvement in the current crisis.