COPENHAGEN, Denmark (AP) — Novo Nordisk is recalling 3 million insulin products used for diabetes treatment in 13 European countries due to a production problem that can affect the strength of the drug.

The Danish drug maker says Friday’s recall affects certain batches of the prefilled insulin pen NovoMix30 FlexPen in Austria, Belgium, Czech Republic, Denmark, France, Germany, Iceland, Luxemburg, Netherlands, Norway and Slovakia.

It also affects three batches of NovoMix30 Penfill cartridges in Britain and Ireland.

Novo Nordisk says a quality control showed 0.14 percent of the products don’t meet the specifications for insulin strength, which could lead to high or low blood sugar levels.

Company spokesman Mike Rulis said there had been no reports of health problems from patients using the affected products, which were first shipped in March.