U.S. Sen. Elizabeth Warren, D-Massachusetts, said Monday that she is working with a bipartisan group of lawmakers to protect states' rights to legalize marijuana.

"I'm working with a bipartisan group to try to roll back the changes that the attorney general has made so that the states can make their own determination about their marijuana laws and how they want to enforce them," Warren said in a brief interview with reporters in Cambridge.

U.S. Attorney General Jeff Sessions recently announced that he was rescinding Obama-era guidelines that said the Department of Justice would not prosecute marijuana crimes in states where marijuana was legal.

U.S. Rep. Barbara Lee, D-California, filed a bill in the House with four co-sponsors that would stop the Department of Justice from prosecuting anyone who is complying with state law on marijuana.

Another 69 members of Congress have proposed an amendment to a spending bill that would stop the Department of Justice from interfering with states that legalize marijuana, according to the Denver Post's the Cannabist blog.

Both of those were House efforts, and members of the Senate are likely to introduce similar legislation in the coming weeks.

Warren said on Facebook and Twitter last week, "States have the right to enforce their own marijuana policies - and I'm working on legislation to make sure it stays that way."

The legislation she is working on has not yet been released. According to Warren's office, more information will be forthcoming in the next couple of weeks.