Hy-Vee leaders on Wednesday advised customers to closely monitor payment card statements after “unauthorized activity” was detected on some of the grocery chain’s payment-processing systems.

The investigation is focused on card transactions at fuel pumps, drive-thru coffee shops and restaurants, including Market Grilles, according to a press release. Those locations have different point-of-sale systems than grocery and convenience stores, which use encryption to make data unreadable.

“It is always advisable to closely monitor your payment card statements for any unauthorized activity,” Hy-Vee officials wrote in the release. “If you see an unauthorized charge, immediately notify the financial institution that issued the card because cardholders are not generally responsible for unauthorized charges reported in a timely manner.”

Authorities have been contacted and “we believe the actions we have taken have stopped the unauthorized activity on our payment processing systems,” officials wrote in the release.

“Because the investigation is in its earliest stages, we do not have any additional details to provide at this time,” the release stated. “We will provide notification to our customers as we get further clarity about the specific time frames and locations that may have been involved.”

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