It's the first time that Francis has openly called for an investigation of genocide allegations over Israel's actions in the Gaza Strip.

Francis has not previously described the situation in Gaza as a genocide in public. But last year he was at the centre of a messy dispute after a meeting with a group of Palestinians at the Vatican, who insisted he had used the word with them in private, while the Vatican said he had not.

In his upcoming book, Pope Francis wrote that the issue of Israel's ongoing genocide of Palestinians in Gaza should be "studied carefully."