The Co-op is recalling chocolate Santas after batteries were found inside two of them.
The retailer said there were two “alleged tampering incidents” involving the hollow milk chocolate figures, which sell for £1.
It has informed the police and Food Standards Agency and started a national product recall.
There was no indication of any blackmail demand or threat, a spokesman said.
The Co-op has sold 165,000 of the German-made Santas, which are available from other retailers, and has advised people not to eat them.
The Santas with batteries were found in two separate locations, some distance apart.
A Co-op spokesman said: “The health and safety of our customers is our top priority. We are concerned about two separate instances of alleged product tampering involving our hollow milk chocolate Santa foil figures, which have been found to contain a small battery inside.
“As a result we have begun a UK-wide product recall. The police and Food Standards Agency are being notified. Customers with one of these products should not eat it but call our customer relations team for a full refund.”
Anyone who is concerned should call 0800 0686 727 for free. The Co-op said no other products were affected.