European supermarket stocks extended declines Tuesday after Amazon.com Inc (AMZN - Get Report) cut prices at Whole Foods Markets (WFM) by as much as 43% on Monday.

British supermarket Wm Morrison plc (MRWSY) was the worst hit Tuesday, falling as much as 2.15% to change hands at 246 pence, extending a three-month decline of 0.73%.

This was the first chance U.K. supermarkets had to react to the price cut and introduction of Whole Foods products on Amazon's U.K. after markets were closed Monday for a public holiday.

Amazon on Monday cut the prices of bananas, large brown eggs, salmon, avocados, baby kale and almond butter, among other groceries at Whole Foods as its $13.7 billion purchase closed.

In the U.K. Whole Foods products were on sale for Prime customers, putting added pressure on Morrisons, whose products are sold through Amazon. In November, the pair extended their tie-up, allowing Prime customers to make a full order and have it delivered within the hour.

The U.K.'s other large supermarkets were also down in morning trading, with J Sainsbury plc (JSAIY) down 1.42% to 233.16 pence and Tesco (TSCDY) losing 1.19% to 182 pence.

Royal Ahold Delhaize (ADRNY) , the Dutch owner of Food Lion, lost 2.06% in Tuesday trading to €14.77, extending a five-day loss of 11.5%. Ahold Delhaize, which also owns Stop & Shop and Hannaford, is seeing pressure on margins in its U.S. division and doesn't expect any margin growth in the second half of the year.

Carrefour (CRRFY) , the world's second largest retailer, was down 1.40% in Paris to €19.32, extending a 5.2% loss over the past five days.

Beyond leaving the "Whole Paycheck" reputation behind, Jim Cramer thinks Amazon is about to turn Whole Foods into a distribution center:

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