WASHINGTON – Pot-smoking patients or their sanctioned suppliers should not be targeted for federal prosecution in states that allow medical marijuana, prosecutors were told Monday in a new policy memo issued by the Justice Department.

Under the policy spelled out in a three-page legal memo, federal prosecutors are being told it is not a good use of their time to arrest people who use or provide medical marijuana in strict compliance with state law.

The guidelines issued by the department do, however, make it clear that federal agents will go after people whose marijuana distribution goes beyond what is permitted under state law or use medical marijuana as a cover for other crimes.

The new policy is a significant departure from the Bush administration, which insisted it would continue to enforce federal anti-pot laws regardless of state codes.

“It will not be a priority to use federal resources to prosecute patients with serious illnesses or their caregivers who are complying with state laws on medical marijuana,” Attorney General Eric Holder said in a statement.

By the government’s count, 14 states allow some use of marijuana for medical purposes. Some medical marijuana advocates say Maryland shouldn’t be included in that group, because the law there only allows for reduced penalties for medical marijuana usage.

The change has critics, including lawmakers who see it as a tactical retreat in the fight against Mexican drug cartels.

Administration officials said the government will still prosecute those who use medical marijuana as a cover for other illegal activity.

The memo, according to officials, is designed to give a sense of prosecutorial priorities to United States attorneys in the states that allow medical marijuana.

It notes that marijuana sales in the United States are the largest source of money for violent Mexican drug cartels, but adds that federal law enforcement agencies have limited resources.