Pope Francis beseeched Americans to end hostility toward immigrants in a historic speech before the U.S. Congress on Thursday, weighing in forcefully on a divisive issue that is stirring debate in the 2016 presidential campaign.

Bringing a message that America"s power and wealth should be used to serve humanity, the 78-year-old pontiff said the United States must not turn its back on "the stranger in our midst."

The leader of the world"s 1.2 billion Roman Catholics called for a worldwide end to the death penalty, which is still used in 31 of the 50 U.S. states, while advocating a more equitable economy to help people "trapped in a cycle of poverty" and a greater effort against climate change driven by human activities.

Francis on Friday is due to address the United Nations General Assembly in New York and to celebrate an open-air Mass in Philadelphia on Sunday.