A fired Wal-Mart security worker confirmed a newspaper interview Wednesday in which he said he was part of a large surveillance operation that spied on company workers, critics, vendors and consultants. The company defended its security practices.

The world’s largest retailer declined to comment on specific allegations made by former security technician Bruce Gabbard, 44, to the Wall Street Journal in a report published Wednesday. Wal-Mart reiterated that it had fired Gabbard and his supervisor last month for violating company policy by recording phone calls and intercepting pager messages.