The resulting liability will not have a materially adverse effect on its financial statements although the amount of liability cannot be determined, the company said in a regulatory filing.

Safeway spokesman Brian Dowling declined to comment beyond what was included in the filing, but said the company was cooperating with the agency.

The DEA was investigating Costco Wholesale Corp last October for prescriptions for controlled substances. The agency had revoked the controlled substance licenses of two CVS Caremark Corp drugstores in Florida in 2012.

Safeway, which also operates Vons and Dominick's stores, reported better-than-expected quarterly profit for the quarter ended June 14.

(Reporting by Mridhula Raghavan in Bangalore and Lisa Baertlein in Los Angeles; Editing by Lisa Shumaker)