The Pope has weighed in on the US presidential election, in a rare move for the pontiff, who is usually politically neutral.

On a return flight from his 12-day tour of Southeast Asia, he urged American Catholics to “choose the lesser evil”.

Pope Francis asserted that Trump’s pledge to deport millions of immigrants was “a grave sin”, whilst Harris’ pro-choice stance on abortion amounted to “assassination”.

However, he insisted: “Not voting is ugly. It is not good. You must vote.

“You must choose the lesser evil. Who is the lesser evil? That lady, or that gentleman? I don’t know. Both are against life, be it the one that kicks out migrants, or the one that kills children.”

Vatican journalist Francis Rocca described the comments as “exceptional”.

“I suppose it reflects the stakes of the US election. Everybody watches the US election with great interest and certainly they do at the Vatican.

"He was careful not to say 'vote for one or the other', but yes I suppose probably he could have demurred or avoided the question more than he did."

There are roughly 52 million Catholics in the US, encompassing a variety of cross-cultural identities. In swing states such as Pennsylvania and Wisconsin, it is estimated that one in every five eligible voters is Catholic.