Pope Francis is set to visit Lesbos later this month to highlight the plight of refugees.
The Greek government confirmed he will travel with the Ecumenical Patriarch Bartholomew, the spiritual leader of the world's Orthodox Christians.
The pontiff has regularly commented on the migrant situation and has previously spoken of Europe's moral obligation to welcome refugees.
Vatican spokesman Revd Federico Lombardi refused to confirm the trip on Tuesday, but said "I don't deny that there are contacts about a possible trip".
However the Greek government released a statement saying the pope and patriarch would be visiting Lesbos on April 14-15 along with Athens' Archbishop Ieronymos, and that prime minister Alexis Tsipras would join them.