Nassau County police said Monday they are trying to determine how two skimming devices were installed on ATMs at 7-Eleven convenience stores.

The skimmers, devices affixed to ATMs that secretly swipe credit- and debit-card information, were discovered at 7-Elevens at 500 W. Old Country Rd. in Hicksville, on Aug. 23 and at 1275 Front St. in Uniondale, on Friday, according to the Crimes Against Property Squad.

Criminals use the skimmers to lift data from debit and credit cards and can use that data to fraudulently access accounts.

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No accounts were compromised and the investigation is continuing, police said in a news release.

Anyone with information can call Crime Stoppers at 800-244-8477. All calls will be kept confidential.