A majority of the state’s medical marijuana dispensaries were forced to stop accepting debit cards from patients Tuesday, after threats of a federal crackdown prompted a key payment processing company to pull out of the Massachusetts cannabis market.

The disruption is exactly what marijuana patients, activists, and businesses feared after a recent tightening in US marijuana policy ordered by Attorney General Jeff Sessions: that the mere specter of prosecutions could subvert the state-regulated cannabis industry, whether or not federal agents actually start arresting operators of licensed dispensaries.

“It was very abrupt and very frustrating,” said Keith Cooper, chief executive of the Revolutionary Clinics dispensary in Somerville, of the payment company’s decision. “It’s a terrible inconvenience for patients, and an additional expense for dispensaries.”

Cooper said the payment company, Florida’s Merchant Services Consulting Group Inc., called his office Monday to say that recent comments by the top federal prosecutor in Massachusetts hinting at a crackdown on cannabis firms and their financial institutions made it “too risky to continue.” As a result, Revolutionary Clinics and at least nine other medical dispensaries of the 17 currently operating in the state will soon only accept cash. [Read more at Boston Globe]