From a New York Times story by Jason Horowitz headlined “Pope Reveals He’s Working on Secret ‘Mission’ of Peace in Ukraine”:

BUDAPEST — Pope Francis said on Sunday that the Vatican was involved in a secret “mission” to stop the war between Russia and Ukraine and that it would do “all that is humanly possible” to return children taken from Ukraine to Russia and reunite families.

The pope’s remarks to reporters aboard the papal plane returning from a three-day trip to Budapest did not specify what the “not yet public” mission entailed. But Francis said he had privately discussed the situation with both Prime Minister Viktor Orban of Hungary and with the representative of the Russian Orthodox Church in Budapest, Metropolitan Hilarion.