Washington — A little-noticed document issued by President Donald Trump has put advocates of medical marijuana on edge, raising questions about the long-term security of programs now authorized in 29 states and the District that have broad public backing.

In a “signing statement” that accompanied Trump’s signature on the bill passed this month to keep the government open, the president noted a handful of objections on legal grounds, including to a provision that prohibits his administration from interfering with state-run medical marijuana programs.

White House aides indicated that none of Trump’s objections to Congress’s work signaled immediate policy changes. But given how vocal Attorney General Jeff Sessions has been toward relaxing marijuana restrictions, those who support the burgeoning industry are worried about what could come next.

“It just creates a lot of uncertainty, and that uncertainty is deeply concerning for patients and providers,” said Michael Collins, deputy director of the Drug Policy Alliance, an organization that has sought to roll back the nation’s war on drugs. “We had thought medical marijuana wasn’t really in play in terms of a crackdown.”

Such concerns are being voiced more broadly about the direction of marijuana policy under the new leadership at the Justice Department.

Sessions last week directed federal prosecutors to get significantly tougher on drug defendants than under the Obama administration. And a task force launched by Sessions is looking at changes in enforcement particularly regarding marijuana, a drug that remains illegal on the federal level despite significant movement in numerous states.

The eight states that have legalized marijuana for recreational use could be at greater risk for federal intervention than those that have only approved dispensing medical cannabis or cannabis-infused products to patients with a doctor’s recommendation.

As a candidate for president, Trump repeatedly voiced support for medical marijuana, a concept that has been increasingly embraced by fellow Republicans at the state level. Of the 29 states that have authorized programs, Trump prevailed in last year’s election over Democrat Hillary Clinton in nine of them.

Meanwhile, a Quinnipiac poll last month found that 94 percent of Americans supported allowing adults to legally use marijuana for medical purposes if their doctors prescribe it.

White House press secretary Sean Spicer said earlier this year that he expects states to be subject to “greater enforcement” of federal laws against marijuana use, though he also said Trump sees “a big difference” between use of marijuana for medical purposes and for recreational purposes. Sessions, however, said at an appearance in Richmond, earlier this year, that medical marijuana “has been hyped, maybe too much.”

A Justice Department spokesman declined to discuss what future steps might be taken related to medical marijuana but said the provision in the spending bill is of concern to officials.

“The Department of Justice must be in a position to use all laws available to combat the transnational drug organizations and dangerous drug traffickers who threaten American lives,” said spokesman Ian Prior, who wouldn’t discuss the issue further.