Pope Francis has been criticised after he compared a refugee centre to "concentration camps." The pontiff had been visiting Rome Basilica where he met with migrants on Saturday 22 April.

He spoke about his visit to a refugee camp on the Greek island of Lesbos last year when he encountered a Muslim refugee from the Middle East who told him how "terrorists came to our country".

Pope Francis said: "I don't know if he managed to leave that concentration camp, because refugee camps, many of them, are of concentration (type) because of the great number of people left there inside them."

Soon afterwards, the American Jewish Committee (AJC) urged the pontiff "to reconsider his regrettable choice of words".

"The conditions in which migrants are currently living in some European countries may well be difficult, and deserve still greater international attention, but concentration camps they certainly are not," David Harris, the head of the AJC, said in a statement.

"The Nazis and their allies erected and used concentration camps for slave labour and the extermination of millions of people during World War II. There is no comparison to the magnitude of that tragedy.

"We respectfully urge the pope to reconsider his regrettable choice of words. Precision of language and facts is absolutely essential when making any historical reference, all the more so when coming from such a prominent and admired world figure."

Several concentration camps across Europe were erected during the Second World War to kill off certain members of German society including Jews, criminals, homosexuals, Romani, and political opponents.