Sleep positioners marketed with the promise of helping babies sleep safely are too dangerous to use and should not be sold, U.S. officials warned on Wednesday.

The deaths and dangerous situations resulting from the use of infant sleep positioners are a serious concern, Consumer Product Safety Commission (CPSC) Chairman Inez Tenenbaum said in a joint statement with the U.S. Food and Drug Administration (FDA).

She said parents and caregivers should stop using these sleep positioners, so that children can have a safer sleep.

In the last 13 years, U.S. officials have received 12 reports of infants who suffocated because of sleep positioner products.

Sleep positioners sometimes are marketed with the claim that they can reduce gastroesophageal reflux disease, so-called flat head syndrome, and Sudden Infant Death Syndrome (SIDS), but can suffocate babies and cause other harm, CPSC and FDA officials said in the statement.

It's great that the FDA is issuing a warning, and unfortunate that a recall would take a lot longer to put into effect, Diana Zuckerman, president of the National Research Center for Women & Families, said in a statement.

We strongly urge parents to ignore the hard sell for many of these infant products, and we beseech companies to be more careful before they sell products that could potentially kill our babies, Zuckerman said.

The warning follows recent actions regarding other children's products, including a recall in June of more than 2 million drop-side cribs and in late April a recall of some liquid children's medicines made by Johnson & Johnson.

The FDA has approved about 18 sleep positioning products over the years, but none were approved to make claims about SIDS.

Right now, our view is that given the risk, the modest evidence of benefit does not outweigh the risk, said FDA Principal Deputy Commissioner and pediatrician Joshua Sharfstein.

The FDA has written in the past month to manufacturers of these products asking them to stop selling them. The agency said five companies had informally agreed, but it did not release their names.

It is unclear how many sleep positioners are on the market because manufacturers that make no medical claim do not need FDA approval.

Most of the models that do make medical claims are manufactured by privately-held companies. They include positioners made by Olympic Medical Corp, Pedicraft Inc, Life Innovations LLC, Kamber Corp, Kaye Products Inc and Premie Comfort Products.