The Interior Department manages around 500 million acres of U.S. public lands, including its national parks, and also administers the country’s onshore and offshore oil and gas leasing programs – source of around a quarter of U.S. oil production. One of the sources said the layoffs include around 800 people from the Bureau of Land Management, which manages millions of federally-owned acres for uses ranging from oil and gas development to timber harvesting, cultural preservation and recreation. The Interior Department did not immediately respond to a request for comment.