A 2001 UN Security document entitled “Replacement Migration: Is It a Solution to Declining and Ageing Populations?” outlines a strategy to “offset population decline and population ageing resulting from low fertility and mortality rates” by importing millions of migrants into various regions of the world each year including Europe, Japan, Russia, Korea, and the United States. The plan seeks to bring 10.8 million migrants to the United States each year until 2050, bringing a total of 593 million by that time.
This Infowars article details the issue.