Pope Francis on Saturday said the Vatican was ready to intervene as a mediator to try and end Venezuela's deadly political crisis under "clear conditions".
Speaking on a plane bringing him back from Egypt to Rome, the pontiff said: "I believe that that must be done under conditions. Very clear conditions."
"There was an intervention by the Holy See following strong pressure" by four former leaders of Spain, the Dominican Republic, Panama and Colombia, he said.
"This did not work because the proposals were not accepted. They were diluted. It was a 'yes, yes but no, no'", he said.
A month of demonstrations in Venezuela has left 28 people dead in clashes between riot police and anti-government protesters, according to prosecutors.
The centre-right-led opposition is demanding elections to remove President Nicolas Maduro. It blames him for an economic crisis that has caused shortages of food, medicine and other basic items.
The pontiff said the four mediators were trying to relaunch the process, adding "they are looking for a venue" but the opposition was against the process.
"We should do all that we can for Venezuela with necessary guarantees," he said.
The pontiff did not clarify the conditions but his Secretary of State Pietro Parolin, the former apostolic nuncio in Venezuela, had in December spoken of four prerequisites: the establishment of an electoral calendar, the freeing of opposition supporters held in prison, allowing foreign health aid and giving back parliament its powers.