LONDON - The World Health Organization (WHO) has asked the Indian authorities for help in establishing the origins of a contaminated cough syrup that has been linked to children's deaths in Cameroon.

The U.N. agency issued a warning on Wednesday about a syrup branded as Naturcold, which was sold in Cameroon and linked by authorities there with at least six children's' deaths. The syrup contained extremely high levels of the toxic contaminant diethylene glycol, the WHO said.

The manufacturer of Naturcold is listed on the packet as Fraken International (England), but the UK regulator told WHO that no such company exists.

The WHO wrote to India's regulator as the alert was issued on Wednesday, asking for help in reaching Indian companies that may be involved, a spokesperson told Reuters. Other countries have also been contacted, she said.

The alert about Naturcold is the latest of several similar warnings issued in recent months about contaminated cough syrups sold worldwide.

In 2022, the medicines were linked to the deaths of more than 300 children in Gambia, Uzbekistan and Indonesia. Another alert earlier this year also said contaminated medicines had been found in the Marshall Islands and Micronesia, but no deaths have been reported there. The WHO has said the threat is ongoing.

All of the syrups are made by different manufacturers, although in three of the four incidents, they are Indian-made. The deaths in Indonesia were linked to syrups made domestically.

The WHO said this pattern meant that working with India was a high priority in finding out more about the incident in Cameroon. It previously said efforts to find out more about the cough syrup incidents and the supply chains involved had been stymied by a lack of information from the Indian authorities and drugmakers.

Officials in India and Cameroon did not immediately respond to requests for comment.

(Reporting by Jennifer Rigby in London; Additional reporting by Krishna N.Das in New Delhi and Amindeh Blaise Atabong; Editing by David Holmes)