Immigration to Israel during the late 1940s and early 1950s was aided by the Israeli Immigration Department and the non-government sponsored Mossad LeAliyah Bet ( "Institute for Immigration B") which organized illegal and clandestine immigration. Both groups facilitated regular immigration logistics like arranging transportation, but the latter also engaged in clandestine operations in countries, particularly in the Middle East and Eastern Europe, where the lives of Jews were believed to be in danger and exit from those places was difficult. Mossad LeAliyah Bet was disbanded in 1953. The immigration was in accordance with the One Million Plan. The immigrants came for differing reasons: some held Zionist beliefs or came for the promise of a better life in Israel, while others moved to escape persecution or were expelled.