VATICAN CITY (Reuters) -Pope Francis went to the Russian embassy to the Holy See on Friday to relay his concern over Russia's invasion of Ukraine to Moscow's ambassador, in an unprecedented departure from diplomatic protocol.

       Vatican spokesman Matteo Bruni said the pope spent about 30 minutes at the embassy, which is close to the Vatican.

       "He went to express his concern over the war," Bruni told Reuters. Bruni would not comment on a report that the pope, 85, had offered the Vatican's mediation.

       It was believed to be the first time a pope has gone to an embassy to talk to an ambassador in a time of conflict. Foreign envoys are usually summoned by the Vatican's Secretary of State or meet with the pope in the Apostolic Palace.

       In an interview with Reuters of Feb. 14, before the invasion, Ukraine's ambassador to the Vatican, Andriy Yurash, said Kyiv would be open to a Vatican mediation of the conflict. [L1N2UP1AH]

       In a statement on Thursday, Vatican Secretary of State Cardinal Pietro Parolin said the Holy See hoped that those who hold the destiny of the world in their hands would have a "glimmer of conscience".

       World leaders have accused Russian President Vladimir Putin of a flagrant violation of international law by launching the biggest attack by one state against another in Europe since World War Two.

       (Reporting by Philip Pullella; Editing by Raissa Kasolowsky)