France, July 4 -- In a letter sent to Americans on the July 4 anniversary, US-born Pope Leo insisted that protecting the unborn and all human life also means "welcoming, protecting and assisting immigrants, whose hopes, sacrifices and contribution have formed part of the history of this country from its very beginning".

"To receive them with compassion and generosity is not only an act of charity, but also a recognition of the dignity that belongs to every human person," Leo wrote.

The Pope had criticised US President Donald Trump's hardline immigration policies before becoming head of the Catholic Church.

The letter came a day after he described how "successive waves of immigrants" had played a role in building the United States. In a...