Pope Francis urged Russian President Vladimir Putin to make a "sincere effort to achieve peace" in Ukraine when the two leaders met privately Wednesday at the Vatican.
During the 50-minute meeting, the pope stressed the importance of adhering to a cease-fire agreement reached in February and also called for humanitarian workers to be allowed access to all parts of the country, the Vatican said in a statement.
Francis has faced criticism for not taking Russia to task for annexing Crimea last year and providing support to pro-Russia insurgents who are fighting for independence from Ukraine.
In February, Francis condemned the conflict as a "war between Christians," drawing protests from Sviatoslav Shevchuk, the head of the Ukrainian Greek Catholic Church, who said the war was the result of a foreign invasion. Ukrainian Catholics "expected more from their spiritual father," Shevchuk said at the time.
Putin has sought to boost Russia's arms industry and has been accused of stirring up the conflict in Ukraine, the kind of behavior that Francis has railed against. In March, the pope called on God to "convert those who seek war, those who make and sell weapons!"
But Francis counts on Russia's support to defend Christians in the Middle East and is also seeking to maintain good relations with the Russian Orthodox Church.
Before Wednesday's meeting, the U.S. ambassador to the Holy See, Kenneth Hackett, said he hoped Francis would take Putin to task on Russia's role in Ukraine.
"We think they could say something more about concern of territorial integrity, those types of issues," Hackett said in Rome. "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."
Putin arrived at the Vatican more than an hour late, exceeding the 50 minutes he made the pope wait at their first meeting in 2013.
The Russian leader flew to Rome from Milan, where he received a warm welcome from Italian Prime Minister Matteo Renzi earlier. Greeting Putin as Russia's "dear" president, Renzi praised his fight against terrorism and asked for his help in ending the anarchy in Libya.
It was a far cry from the tough words that President Obama had for Putin this week. At a gathering of major industrialized countries in Germany, Obama said Russia's intervention in Ukraine suggested that Putin was trying to re-create "the glories of the Soviet empire."
The Russian leader was not invited to the G-7 meeting.
Italy has backed Western sanctions on Russia but is worried about losing valuable trade with the country — a fear Putin was quick to allude to Wednesday.
"If the sanctions against Russia are not withdrawn, Italian companies will lose contracts" worth more than $1 billion, Putin said while touring the Milan World's Fair with Renzi. "We can find other partners, but it would be a shame to give up our collaboration with Italy."
Putin called Italy "a great partner of Russia in Europe," adding that their relationship dated back 500 years.
Italy has often sought to act as a middleman between Russia and the West, offering a channel of communication with the United States.
But trade was the main issue for the large group of Italian industrialists who joined Renzi and Putin at their meeting in Milan.
The Italian employers organization Confindustria has said that a Russian embargo imposed in response to Western sanctions cost Italy's luxury industry $566 million in exports in 2014.