The United States urged the Vatican on Wednesday to criticize Russia's involvement in the Ukraine conflict more forcefully, hours before Pope Francis was due to meet Russian President Vladimir Putin.
"It does seem that Russia is supporting the insurgents and does seem that there are Russian troops inside Ukraine," said Ken Hackett, the U.S. ambassador to the Vatican.
"Maybe this is an opportunity where the Holy Father can privately raise concerns. Certainly Pope Francis has been told about the situations that are happening in eastern Ukraine ... so is he is not unaware," Hackett said.
Last February, when the pope referred to the conflict in the Ukraine as a "war between Christians" without criticizing Moscow, the Russian Orthodox Church praised it as a balanced approach.
But the Vatican had to issue a clarification after one Ukrainian Catholic bishop called the pope's words "particularly painful" for all Ukrainians.
Western countries, Kyiv and NATO have all presented what they say is evidence that Russia is sending troops and weapons to rebels in eastern Ukraine, although Moscow vigorously denies this.
Putin has expressed concern about the fate of Christians in the Middle East, particularly in Syria, and this is also expected to be a topic of discussion in his meeting with Francis, their second since Francis' election.
"I'd like to see if he (Putin) has a proposal (about protecting Christians). That would be very useful," said Hackett, who spoke during a briefing on a new accord on the exchange of financial information between the Washington and the Vatican.