LONDON (Reuters) -Amazon.com said it planned to close all of its 19 Amazon Fresh UK convenience grocery stores, of which five would be converted to its Whole Foods Markets brand, less than five years after it entered the market.

Amazon Fresh pioneered "walk out" technology in Britain, enabling customers to skip the checkout line when they picked up groceries, including its own "by Amazon ( AMZN )" brand.

It said on Tuesday it had taken the difficult decision to propose closing the stores after evaluating the business and the substantial growth opportunities in online delivery.

It said it was seeing strong demand for household essentials and groceries from its Amazon.co.uk store, Amazon Fresh online, Whole Foods Market and its online delivery partnerships with Morrisons, Co-op, Iceland and Gopuff.

Next year it said it planned to introduce perishable groceries alongside everyday essentials and other products on Amazon.co.uk with same-day delivery.

In addition to expanding online grocery, it said it would convert five Amazon Fresh locations to Whole Foods Market, the U.S. chain it bought in 2017.