As many as 96 people are now thought to have died in Argentina after being treated with medical-use fentanyl that was tainted with bacteria.

The official death toll stands at 87, and a judicial source has told the Buenos Aires Herald that nine further deaths are under investigation.

The alarm was first raised in May, when dozens of hospital patients suffered serious bacterial infections. Strains of the bacteria Klebsiella pneumoniae and Ralstonia pickettii – some of which were resistant to multiple antibiotics – were detected in the patients.