Pompeo and his wife later went to the Athens Cathedral for Sunday mass
The Greek PM raised the issued of Turkish provocations in the wider region
"Sanctioning a NATO ally a very, very serious action"
Pompeo met with Greek Foreign Affairs Minister Nikos Dendias
"Greece is a pillar of stability in the Eastern Mediterranean and Balkans and an important NATO ally"
Last year, Pompeo called on the UN to establish a new day of global remembrance for victims of religious persecution
But Trump has sent mixed signals about how he might respond to Turkey
Turkey is losing its grip...
This is the first official visit of Pompeo as the 70th US secretary of state to Russia
Pompeo: "Next week I am hopeful I will be able to announce another series of actions that we will jointly take together"