VATICAN CITY — Pope Francis met privately with Russian President Vladimir Putin at the Vatican on Wednesday, using the talks to call for a sincere effort aimed at bringing peace to Ukraine.

Vatican spokesman the Rev. Federico Lombardi said their talks concentrated on the Ukraine conflict and the Middle East, where the Holy See is worried about the fate of the Christian minority.

Putin earlier Wednesday met Italian Prime Minister Matteo Renzi in Milan and arrived an hour late to the meeting at the Vatican — his second with Francis since he became pope in 2013.

Lombardi said Francis stressed the need “to commit oneself in a sincere and great effort to bring” peace to Ukraine, through dialogue and implementation of the Minsk accords.

Francis also urged access to humanitarian aid.

The United States, using diplomatic channels, had encouraged the Vatican to use the private papal audience as an occasion to join the West in condemning Moscow’s actions in Ukraine.

On Wednesday, the US ambassador to the Holy See, Kenneth Hackett, said the US would like to see the Vatican increase its concern about what is happening in Ukraine during the pope’s meeting with Putin.

“We think they could say something more about concern of territorial integrity, those types of issues,” Hackett told reporters. “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.”

Earlier Wednesday, however, Putin won lavish praise from Renzi as a crucial player in international anti-terrorism efforts, as Renzi sought the Russian president’s help in ending the conflict in Libya that has fueled the Mediterranean migrant crisis.

Renzi greeted Putin as Russia’s “dear” president and didn’t voice any criticism against the country’s actions in Ukraine, saying simply that they agreed there must be full implementation of the Minsk peace accord.

Renzi met Putin after a tour of Russia’s pavilion at Milan’s Expo.

At a brief Russian-Italian news conference in Milan, Putin stressed the price Italian businesses are paying for the economic sanctions lodged by the European Union against Russia, which annexed Crimea from Ukraine during the conflict.

Putin noted how several infrastructure projects, won in bidding by Italian companies, were stalled because of sanctions against some Russian financial institutions. Likewise, sanctions forced the cancellation of some contracts in the military sphere, costing 1 billion euros ($1.1 billion) in earnings for Italian companies, Putin said.

The leaders of the world’s industrialized democracies for a second year in a row refused to let Putin join their G-7 summit, which ended earlier this week. They said sanctions against Russia won’t be lifted until Moscow fully implements its part of the Ukraine peace accord, and could be increased if needed.

Russia accuses Ukraine of failing to launch political dialogue with the rebellious east and of keeping its economic blockade of areas controlled by pro-Russian rebels. Kiev, the United States, NATO and European leaders have blamed Moscow for supplying rebels with manpower, training and weapons. Russia denies the claims.

Both Putin and Renzi spoke confidently of moving forward after the eventual full implementation of the Minsk peace accords.

Renzi praised Russia for being “in the front row in facing the global threats we are all facing.”

Citing Russia’s role as a permanent member of the UN Security Council, he said Italy “needs Russia’s help on the Libyan question.” Renzi didn’t give specifics on what he hoped Russia might do on Libya.

People-smugglers have been flourishing in Libya amid the confusion, violence and chaos that followed the demise of Moammar Khadafy’s dictatorship in 2011. Rival Libyan governments and tribal and militia fighting so far have combined to thwart Italy’s calls for reconciliation and pacification in Libya as a way to combat the smuggling.

While the pope has deplored the loss of life in Ukraine and called for all sides to respect the cease-fire, he has not publicly placed any blame on Russia in an apparent bid to not upset Vatican relations with the Orthodox Church and in hopes of engaging Russia’s help to confront the persecution of Christians in the Middle East.

Hackett, the US ambassador, noted that Putin had spoken about the plight of Christians and that that was clearly an area of concern for the Vatican.

“I’d like to see if he’s got a proposal,” he said of Putin.

A cease-fire agreement for Ukraine has been shaky. The heaviest fighting in months broke out in recent days between pro-Russian separatists and Ukrainian forces.

After meeting with the pope, Putin was expected to spend time later Wednesday with his old friend, ex-Premier Silvio Berlusconi.