Pope Francis told Congress yesterday that the US should reject a “mindset of hostility” to immigrants, directly addressing a thorny subject that is dividing the country and stirring debate in the 2016 presidential campaign.

In a historic first speech by a Pope to a US Congress, the Argentine Pontiff said the US must not turn its back on “the stranger in our midst.”

“Building a nation calls us to recognise that we must constantly relate to others, rejecting a mindset of hostility,” the 78-year-old Pope told the Republican-dominated legislature.

Pope Francis, the son of Italian immigrants to Argentina, delivered a wide-ranging speech in English that took on issues dear to liberals in the US and also emphasised conservative values and Catholic teachings on the family. He called for support in fighting climate change, a more equitable economy, and an end to the death penalty. In reference to abortion and euthanasia, the Pope said humanity must “protect and defend human life at every stage of its development.”

The traditional family is threatened, perhaps as never before

Aversion to illegal immigrants has featured heavily in the race for the Republican presidential nomination. Front-runner Donald Trump says he would deport the 11 million undocumented immigrants if he were elected to the White House.

Speaking softly and in heavily accented English to a packed House of Representatives chamber, Pope Francis said America should not be put off by the number of immigrants who are trying to make it their home.

“We must not be taken aback by their numbers, but rather view them as persons, seeing their faces and listening to their stories, trying to respond as best we can to their situation. To respond in a way which is always humane, just and fraternal,” he said.

The US saw a flood last year of more than 60,000 unaccompanied minors from Central America rushing to the US border hoping to get in.

A frequent critic of the damage caused to the environment by capitalism’s excesses, the Pope said Congress has an important role to play to “avert the most serious effects of the environmental deterioration caused by human activity.”

In comments welcomed by conservatives, Pope Francis expressed concern about threats to the family, a reference to same-sex marriage after a US Supreme Court ruling in June that made gay marriage legal across the country.

Pope Francis said the traditional family “is threatened, perhaps as never before, from within and without. Fundamental relationships are being called into question, as is the very basis of marriage and the family.”