Retail giant Amazon is continuing to sell baby sleep positioners despite fears they can cause babies to suffocate.

Several other firms, including John Lewis and Tesco, have removed the products from their websites after US authorities issued a fresh warning to parents saying they were unsafe.

The US Food and Drug Administration (FDA) has linked the products to at least 12 baby deaths in America which occurred when babies rolled from their side to their front and suffocated.

The positioners, sometimes called nests or wedges, are intended to keep the baby in one place on their back and are marketed as suitable for use up to six months of age.

Some parents use them hoping their baby will sleep longer due to the infant feeling cosy, while others believe they cut the symptoms of reflux.

While some retailers have taken action to remove the products from their websites, others, including Amazon and Jo Jo Maman Bebe, still have them for sale.

A spokeswoman for Jo Jo Maman Bebe said it was still selling the products but was "investigating the issue as a matter of urgency with our suppliers".

A spokeswoman for Amazon, which still has a range of sleep positioner products for sale, said the firm would not comment on the issue.

John Lewis has removed the Cocoonababy Sleep Positioner from sale and has also withdrawn the Cocconababy Nest sleep pod as "an additional precaution".

It is still selling its range of Sleepyhead pods, telling customers on Twitter the product was not considered a sleep positioner and was therefore still on sale.

A statement from John Lewis said: "We have one baby sleep positioner, the Cocoonababy Sleep Positioner which has been removed from sale.

"As an additional precaution we have also withdrawn the Cocoonababy Nest, which is a sleep pod, while we await further advice and reassurance from the supplier."

A Tesco spokesman said: "We have removed these products from our website as a precautionary measure."

Several of the products were still available on eBay but a spokeswoman said it was planning to remove them.

She said: "Following recent recommendations by US authorities, items of this nature will now be prohibited from being sold on our platform.

"Our team will be informing sellers and removing any listings that contravene our policies."

Mothercare has also removed some products from sale.

Individual manufacturers are still selling the products via their websites.

The FDA said it was "reminding parents and caregivers not to put babies in sleep positioners".

"These products - sometimes also called ‘nests' or ‘anti-roll' products - can cause suffocation (a struggle to breathe) that can lead to death," it said.

"The two most common types of sleep positioners feature raised supports or pillows (called ‘bolsters') that are attached to each side of a mat, or a wedge to raise a baby's head.

"The positioners are intended to keep a baby in a specific position while sleeping and are intended for infants under six months old."

The FDA and the NHS recommend infants sleep on their backs on a flat mattress in an empty crib.

The FDA said its safety advice was to "never use infant sleep positioners.

Using this type of product to hold an infant on his or her side or back is dangerous".

"The federal government has received reports about babies who have died from suffocation associated with their sleep positioners," it said.

A spokeswoman for Boots said: "At Boots UK, the quality and safety of the products we sell is of the utmost importance to us.

"We are removing the sale of all sleep WEB positioner products whilst we investigate further with our suppliers."

Mothercare has removed the Babymoov Cosydream from sale, and Babymoov told the Guardian: "We would like to assure customers that our award-winning, paediatrician-approved Cosydream has never been involved in any incident connected with infant fatality.

"Nor does the Cosydream resemble the products that first gave rise to the FDA guidelines seven years ago … our Cosydream has never been sold in the United States and thus can't be involved in the incidents [cited by the FDA].

"Over 100,000 Cosydream units have been sold to satisfied customers worldwide since the product was first launched four years ago."