DENVER — Colorado already is being sued by two neighboring states for legalizing marijuana. Now, the state faces an additional federal lawsuit from its own citizens.

Plaintiffs who oppose legal pot are appealing to federal courts to try to shut down Colorado's $800-million-a-year marijuana industry. They plan to announce details of the claim Thursday morning at the state Capitol.

The lawsuit is being sponsored by a group called the Safe Streets Alliance, which is based in Washington D.C. and opposes marijuana legalization.

Colorado is also being sued by Nebraska and Oklahoma for legalizing marijuana in 2012. In that case, Colorado has until March 27 to tell the U.S. Supreme Court why it thinks Nebraska and Oklahoma are wrong.