The founder of the once-criticized liberation theology has praised the "new climate" at the Vatican under Pope Francis that has focused the church's attention on serving the poor.

Peruvian theologian the Rev. Gustavo Gutierrez made his first appearance at an official Vatican press conference Tuesday.

It was a remarkable moment given that the Vatican spent much of the past few decades cracking down on individual priests and the Marxist excesses of the Latin American-inspired theology advocating the church's preferential option for the poor.

Gutierrez stressed that the Vatican never condemned liberation theology as a whole. But he acknowledged that it had engaged in "very critical" dialogue with its proponents and that there were "difficult moments."

He said: "I'm happy to be here."