VATICAN CITY (CNS) -- Under the gaze of a painting of "Mary, Untier of Knots" and with dozens of diplomats from around the world, Cardinal Pietro Parolin, Vatican secretary of state, celebrated a Mass for peace in Ukraine.

In the presence of Andrii Yurash, Ukrainian ambassador to the Holy See, and Aleksandr Avdeyev, his Russian counterpart, Cardinal Parolin repeated Pope Francis' insistence that the Russian invasion of Ukraine was a "war" and not simply a "military operation," as Russian President Vladimir Putin repeatedly claimed.

"We are convinced that prayer is never useless," the cardinal told the diplomats at the Mass March 16 at the Altar of the Chair in St. Peter's Basilica. "Prayer can affect even the most humanly desperate situations. Most of all, it can change hearts and minds."

The prayers of the faithful were read in several languages, including Russian and Ukrainian.

The Gospel at the Mass was the one prescribed for the day, recounting how the mother of James and John asked Jesus to allow one of her sons to sit at his right and the other at his left, a request for privilege that showed that she, "like all mothers, wants the best for her sons," the cardinal said.

Jesus tells the disciples, "Whoever wishes to be great among you shall be your servant; whoever wishes to be first among you shall be your slave."

"Do you not think, brothers and sisters, that if we really put the words of Jesus into practice, all the conflicts on the earth would gradually disappear?" the cardinal asked. "Do you not think, brothers and sisters, that if we listened a little more to the invitation of our Lord, weapons would be silenced, indeed they would not even have to be built?"

One who believes in Christ, he said, testifies in word and deed that "the glory of God is not to oppress, but exactly the opposite; and it is that glory that truly fills the world with beauty, with goodness, that gives life and builds peace."

When Jesus said, "Peace I leave with you; my peace I give to you," it was a pledge to his disciples of all times, the cardinal said, which is why "the disciple of Jesus never loses hope."

"Those who seriously love the peace of Christ," he said, "those who, amid a thousand obstacles and a thousand oppositions, bear witness to it, those who in prayer every day ask the Lord for true peace to reign, they effectively contribute, at least a little, to making the earth more merciful and more human."

Representing countries from every part of the world, he said, the diplomats "turn to God 'with a heart broken by what is happening in Ukraine,' repeating with Pope Francis: 'Silence the weapons! God is with the peacemakers, not with those who use violence.'"

Patrick Connell, chargé d'affaires of the U.S. Embassy to the Holy See, said the embassy "stands with the many diplomatic missions who joined me at St. Peter's today -- as well as the millions around the world -- against President Putin's brutal, unjustified and unprovoked war against Ukraine and its people."

"We appreciate the Vatican's efforts to help restore peace, as well as the care of the Catholic Church for the millions of refugees from this war," Connell said.

"As Russian soldiers continue to die needlessly in Ukraine and the economic consequences of the war mount in Russia, the world remains open to genuine diplomacy," he said in a statement. "We will, together with our Ukrainian partners and our allies and partners around the world, continue to pursue every avenue to de-escalate the conflict, end the bloodshed and save lives."