Attorney General Jeff Sessions said Tuesday that he is “dubious about marijuana,” hinting that the Trump administration could be ready to block states from selling it for recreational use.

“States, you know, can pass whatever laws they choose, but I’m not sure we’re going to be a better, healthier nation if we have marijuana being sold at every corner grocery store,” he said in a speech at the winter meeting of the National Association of Attorneys General. “We’ll have to work our way through that.”

Sessions made his remarks after White House Press Secretary Sean Spicer told reporters last Thursday that the Department of Justice would use the federal law banning marijuana to crack down on recreational pot sales while allowing states to regulate the drug for medical use.

Voters in eight states have legalized recreational marijuana: Washington, Colorado, California, Massachusetts, Maine, Nevada, Oregon and Alaska.

The Obama administration’s Justice Department gave states the green light to tax and regulate the drug as long as they promised to do a good job of policing themselves. But it will be up to Sessions to decide whether he wants to continue the largely hands-off approach or lead a new national crackdown.

Legalization backers were quick to criticize Sessions for suggesting that pot might be sold “at every corner grocery store.”

“No states allow this,” said Tom Angell, chairman of Marijuana Majority, a pro-legalization group.

As a presidential candidate, Trump said that he would leave the question of legalization to individual states. But his choice of Sessions in November set off immediate panic among legalization backers.

Sessions, a longtime opponent of legalization as a former Republican senator from Alabama, caused a stir last year when he said at a Senate hearing that “good people don’t smoke marijuana.”

At his confirmation hearing in January, Sessions gave conflicting signals on what he would do. In Washington state, where voters legalized recreational marijuana in 2012, the uncertainty has many politicians worred about a possible crackdown.

When Sessions was asked at his confirmation hearing whether he would use federal resources to investigate and prosecute sick people who use medical marijuana, he replied: “I won’t commit to never enforcing federal law.”

But he also said that enforcing the law is “a problem of resources for the federal government.” And he said that Obama’s Justice Department had set out policies that are “truly valuable in evaluating cases.”

Sessions also said that Congress should set marijuana policy and the attorney general should enforce the law.

“I think one obvious concern is that the United States Congress has made the possession of marijuana in every state, and distribution of it, an illegal act. ... We should do our job and enforce laws effectively as we’re able,” Sessions said.