(Reuters) – A coalition of 14 attorneys general condemned payment networks majors including Visa Inc, American Express Co and Mastercard Inc for pausing work on a merchant code to help detect suspicious gun sales in the United States.

The group, led by New Jersey AG Matthew Platkin, condemned the firms for buckling under political pressure, in a letter sent to the chief executives of the companies, and called their action “unjustifiable” on Thursday.

Visa, Mastercard and American Express did not immediately respond to Reuters requests for comment.

The credit card companies last week said they had paused work on a new merchant category code (MCC), citing Republican pushback in various U.S. states on concerns about improper tracking of consumer behavior.

“We see no valid reason why these companies, who process millions of transactions in firearms, ammunitions, gun kits, and more, would renege on their pledge to take…steps to help flag potential gun traffickers and mass shooters,” said AG Platkin in the letter.

U.S. Senators Bob Menendez and Elizabeth Warren have also called on federal regulators to help speed up the adoption of the MCC by payment networks.

The MCC, aimed at identifying firearms sellers, would identify the type of store where consumers shopped, though not the individual items they bought.

(Reporting by Deborah Sophia in Bengaluru; Editing by Shinjini Ganguli)