Pope Francis has apologised to refugees for the lack of welcome shown them in the societies where they have sought refuge.

The Pope sent a video message to Rome's Astalli Centre, part of the Jesuit Refugee Service founded in 1981, for its 35th anniversary celebrations.

In his message to the refugees, volunteers and employees at the centre, he said that those who had been forced to flee their homes were brothers and sisters with whom we "share bread, homes and life".

"You are witnesses of how our clement and merciful God can transform the evil and injustice you have suffered into a good for all."

Francis said that every refugee "who knocks on our doors bears the face of God, the flesh of Christ. Your experience of pain and of hope reminds us that we are all foreigners and pilgrims on this earth, welcomed by someone with generosity and without reward."

He said: "Too many times you have not been welcomed! Forgive the closure and indifference of our societies that fear the change in lifestyle and mentality that requires your presence. You are treated like a burden, a problem, a cost, but are, instead, a gift."

He urged the Astalli Centre to continue its work with refugees, saying: "Continue walking alongside them in their journey. Accompany them and be guided by them: refugees know the ways that lead to peace, because they know the acrid odour of war."

Francis drew worldwide attention to the plight of refugees who had crossed the Mediterranean on dangerous small boats from Turkey when he visited a camp on the Greek island of Lesbos last Saturday. He brought 12 refugees back to the Vatican with him to be cared for by the Catholic community of Sant'Egidio.

It was a symbolic gesture to indicate Francis' solidarity with those suffering as a result of fleeing war and persecution in countries like Syria, Iraq and Eritrea. "All refugees are children of God," he said on the flight back to Rome, adding that the decision to bring the refugees with him was "an inspiration of the Holy Spirit".