Pope Francis encouraged mothers to breastfeed their children during a baptismal service at the Sistine Chapel on Sunday.

"You mothers give your children milk and even now, if they cry because they are hungry, breastfeed them, don't worry...Because they are the most important people here," he said, reportedly departing from his prepared homily to expressly reassure that breastfeeding was acceptable.

Francis baptised 33 infants in total, and asked those gathered to remember those across the world who can't afford to "give food to their children".

The Pope has previously voiced his support for breastfeeding. In an interview with La Stampa in December, he recalled an encounter with a mother at a general audience whose baby was crying.

"I said to her: 'Madam, I think the child's hungry.' 'Yes, it's probably time...' she replied. 'Please give it something to eat!' I said. She was shy and didn't want to breastfeed in public, while the Pope was passing. I wish to say the same to humanity: give people something to eat!" Francis said.

"That woman had milk to give to her child; we have enough food in the world to feed everyone. If we work with humanitarian organisations and are able to agree all together not to waste food, sending it instead to those who need it, we could do so much to help solve the problem of hunger in the world. I would like to repeat to humanity what I said to that mother: give food to those who are hungry! May the hope and tenderness of the Christmas of the Lord shake off our indifference."

Francis also made headlines this weekend for insisting that caring for the poor and his criticism of capitalism is not a Communist ideology, but the "touchstone" of Christianity.

"Caring for our neighbour, for those who are poor, who suffer in body and soul, for those who are in need: this is the touchstone. Is it pauperism? No. It is the Gospel," he is quoted as saying in an upcoming book about his economic and social teachings, according to AP.

"The Gospel does not condemn the wealthy, but the idolatry of wealth, the idolatry that makes people indifferent to the call of the poor," he adds.

"This concern for the poor is in the Gospel, it is within the tradition of the church, it is not an invention of communism and it must not be turned into some ideology, as has sometimes happened before in the course of history."

The Pope has been accused of siding with Marxism in the past, but has previously declared that Communists have merely "stolen the flag of Christianity". Karl Marx "did not invent anything," he said.

"I can only say that the Communists have stolen our flag. The flag of the poor is Christian. Poverty is at the centre of the Gospel," he said in an interview with Rome newspaper Il Messaggero in July 2013.

Citing scripture which underlines the need to help those who are vulnerable, Francis added: "Communists say that all this is Communism. Sure, 20 centuries later. So when they speak, one can say to them: 'but then you are Christian'".

The Pope has repeatedly called for a "poor church for the poor," declaring in his apostolic exhortation: "I prefer a church which is bruised, hurting and dirty because it has been out on the streets, rather than a church which is unhealthy from being confined and from clinging to its own security".