VATICAN CITY (Reuters) -Pope Leo made an urgent plea for the world to help immigrants in his first major document, which was released on Thursday and invoked one of the late Pope Francis' strongest criticisms of U.S. President Donald Trump's anti-immigration policies.

Leo's document, known as an apostolic exhortation, is focused on the needs of the world's poor. It calls for widespread changes to the global market system to address rising inequality and to help people living paycheck-to-paycheck.