WASHINGTON — The Obama administration, taking the first regulatory step to accommodate the country's growing state-approved marijuana businesses, issued guidelines Friday designed to bring dispensaries into the banking system and end their risky reliance on stashing large amounts of cash.

The step was a cautious one, reflecting conflicting pressures on the administration.

On one side, many states now allow the sale of marijuana for medical or recreational use. Atty. Gen. Eric H. Holder Jr. said last month that law enforcement agencies were increasingly concerned about marijuana sellers who are forced to deal in cash because the banks' unwillingness to deal with them prevents them from using credit cards.

At the same time, federal law still classifies marijuana as illegal, and many in law enforcement agencies have privately criticized the administration's actions to rein in prosecutions.

The move drew praise from marijuana advocates but seemed likely to fall short of the reassurance banks have sought that they will be free from the risk of prosecution if they deal with marijuana-related transactions.

The effect on California's dispensaries is even more in doubt. The new guidelines say "a financial institution may reasonably rely on the accuracy of information provided by state licensing authorities." Although some California cities and counties regulate the stores, the state has passed no laws to control them.

That uncertainty could increase pressure on the state Legislature to regulate medical marijuana dispensaries, but a bill to create a comprehensive statewide system has had difficulty getting any traction in Sacramento.

Robert Jacob, executive director of the Peace in Medicine dispensary in Sebastopol, Calif., was still optimistic about the federal move.

"I think this is an important first step and a sign that the federal government agrees that responsible regulation is better than turning a blind eye," he said.

Jacob, who is also the city's mayor, said he had approached every bank in Sonoma County to open an account. Two banks agreed, but both later sent him notices saying they were going to have to shut down the accounts.

Steve DeAngelo, who deals with millions of dollars in cash as the head of Harborside Health Center in Oakland, one of the country's largest dispensaries, called it a "baby step." But, he added, "There is a great opportunity here for some forward-thinking, courageous bankers to step up and do the right thing."

The guidelines issued by the Justice and Treasury departments say that if banks follow new procedures and avoid marijuana businesses that raise red flags, such as selling to minors, prosecution "may not be appropriate."

Bankers and their advisors wondered how they could be expected to enter the legal limbo created by the new policy.

Frank Keating, president of the American Bankers Assn., said banks "appreciate the efforts" but noted they would not "alter the underlying challenge for banks."

"Possession or distribution of marijuana violates federal law, and banks that provide support for those activities face the risk of prosecution and assorted sanctions," he said.

Experts were skeptical.

"We believe the vast majority of banks — especially publicly traded banks — will avoid marijuana retailers despite the guidance," said Jaret Seiberg, a senior policy analyst with financial services firm Guggenheim Partners. "The risk of a violation, in our view, far outweighs any monetary benefit."

Two states, Colorado and Washington, voted more than a year ago to allow the sale of marijuana for recreational, as well as medical, use, and 18 states — including California, Illinois and Connecticut — and the District of Columbia allow it for some medical purposes.

The Justice Department indicated in August that it would not attempt to block the implementation of those laws as long as marijuana businesses did not sell across state lines or cross other red lines.

President Obama and Holder have indicated that they have no desire to be tough on pot. Obama said in a New Yorker article published in January that marijuana use is not more dangerous than alcohol.