Massachusetts regulators on Thursday approved four new retail pot shops, more than doubling the number of that have received sign-offs.

The companies behind the shops, which will be located in the Berkshires as well as Hudson and Fall River, must still meet several conditions before they can receive a "commence operations" certificate and open their doors to customers. That means openings are likely weeks away.

"I think this is the clip we're going to be operating at, and if anything it's probably going to get little more voluminous," Steve Hoffman, chairman of the Cannabis Control Commission, told reporters after the regulatory agency met.

Asked why weeks pass between final approval and "commence operations" certificates, Hoffman said it's largely due to companies needing to load their inventory into the state's seed-to-sale tracking system and asking the agency to come in and inspect the inventory afterwards.

"It's literally just entering the inventory and allowing us to do a physical inventory to compare," Hoffman said. "So I don't know physically if that can happen any less than two to three weeks, but it seems like that two to three week cycle is what's going to be typical between final license and certificate to operate, or commence operations."

That's in part due to some of the moratoriums in place at cities and towns expected to expire at the end of this year, he noted.

Two shops have been open since Nov. 20 and pulled in more than $7 million in sales.

The first retail pot shops to open east of the Mississippi, Cultivate in Leicester and New England Treatment Access (NETA) have steadily drawn crowds.

A third retail shop, run by Alternative Therapies Group, is set to open on Saturday, Dec. 15, in Salem. It will be the first such store in eastern Massachusetts.

INSA in Easthampton and Pharmacannis in Wareham, while they are in the final stage of approvals, are still waiting to the okay to commence operations.

The Massachusetts Cannabis Control Commission approved four stores on Thursday, located in Hudson, Pittsfield, Great Barrington and Fall River.

Northeast Alternatives Inc. is aiming to open a shop in Fall River while Theory Wellness, Inc. applied to open a retail shop in Great Barrington. Temescal Wellness of Massachusetts Inc. has retail shops planned for Hudson and Pittsfield.

The commission's votes at a meeting inside the Massachusetts State House brings the total number of retail shops that have received approvals to nine.

This post was updated with comments from Chairman Hoffman.