The United States Justice Department will not challenge laws in the two states, Colorado and Washington, which legalized the recreational use of marijuana, UPI.com reported.

The Justice Department signaled a significant shift in its handling of the disparity between permissive state laws and stricter federal bans on cannabis.

"The Department's guidance in this memorandum rests on its expectation that states and local governments that have enacted laws authorizing marijuana-related conduct will implement strong and effective regulatory enforcement systems that will address the threat those state laws could pose to public safety, public health, and other law enforcement interests," a memo released by the Department of Justice reads.

Colorado Governor John Hickenlooper said that "today's announcement shows the federal government is respecting the will of Colorado votes. We share with the federal government its priorities going forward."

Senate Judiciary Committee Chairman Pat Leahy also applauded the move, saying in a statement that "the Justice Department should focus on countering and prosecuting violent crime, while respecting the will of the states whose people have voted to legalize small amounts of marijuana for personal and medical use."

In 2014, Oregon and Alaska are likely to see ballot-initiated marijuana votes. And in 2016, the Marijuana Policy Project is aiming to get similar measures on the ballot in five more states, which include California, Oregon, Arizona, Nevada, and Maine, NBC News reported.