Jerry Falwell Jr, president of the evangelical Liberty University and bastion of the religious right, has rowed back from a spat with Pope Francis.

As one of Donald Trump's major protagonists in the US church, the two are likely to disagree on many issues.

But on Monday evening Falwell tweeted a stinging critique of the leader of the world's 1.2 billion Catholics before hastily deleting it.

"I do not judge people or politicians," the pope told the Italian newspaper La Repubblica when asked about Trump. "I only want to understand what suffering their behaviour causes to the poor and the excluded."

Falwell tweeted in response: "Pope Francis lost all credibility when he failed to call out US Left for policies that impoverished inner cities for Dem political gain."

The tweet was almost immediately deleted and Falwell later told RNS his wife Becki and 16-year-old daughter Caroline had made him take it down.

But he stood by the tweet and said it was him "thinking out loud" about Francis' politics.

"I couldn't help but think, 'Where were you the last eight years when Obama's policies were further impoverishing the inner cities through these welfare programs that give people just enough to survive but to keep them dependent on the government?'" he said.

"It's my opinion the Democrats do it for their own political gain. I would like to see the pope speak out against that."

He added: "I was just curious why he was taking sides. It seems like the policies of the right to bring jobs back and fair trade deals and to provide jobs to folks in poverty would be something he would cheer for or something he would appreciate."

Earlier this year the Pope and Trump fell out after Francis questioned the Republican's attitude towards immigration during a trip to Mexico. "A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian. This is not the gospel," Francis said after his official visit.

Trump responded by saying Francis' remarks were "disgraceful".

But the majority of Catholics ended up voting for the New York billionaire, according to exit polls that showed 52 per cent backing Trump and 45 per cent supporting Clinton.

Catholic bishops have since voiced concern about Trump's leadership and on the first day of their autumn conference called on the President-elect to change course over his immigration policy.

"Children are afraid; men and women are worried and anxious, thinking about where they can run and hide. This is happening tonight, in America," said Mexican-born Archbishop Jose Gomez who is in line to become the first Latino to lead the American hierarchy.

"Tonight we promise our brothers and sisters who are undocumented — we will never leave you alone," he added. "In good times and in bad, we are with you. You are family. We are brothers and sisters."