The Justice Department told U.S. attorneys today that tribes will be allowed to grow and sell marijuana on reservations, even in states where the drug remains illegal.

The move could open the door for legal pot sales in almost every state, though Justice Department officials said the transactions will be tightly regulated and must meet all federal regulations, the LA Times reports.

Alabama is home to one Native American reservation. The Poarch Creek Indian Reservation is located in south Alabama and the tribe operates Wind Creek Casinos.

The policy change comes following a 2013 Justice Department decision to stop federal marijuana prosecution in states that have legalized sale or possession of the drug. Colorado, Washington, Oregon, Alaska and the District of Columbia have all legalized some form of marijuana sale orpossession.

There will be regulations on tribes wanting to enter into the marijuana business. The Justice Department said they must maintain a "robust and effective" regulatory system, including prohibitions against selling to minors. The memo says that U.S. attorneys will still get involved in marijuana prosecutions when requested by tribal leaders.

There are 326 federally recognized American Indian reservations in the U.S., according to the Bureau of Indian Affairs.