The Norwegian military Friday said it has opened an inquiry after dozens of soldiers reported feeling ill after target practice with a new assault weapon and a new type of ammunition.
Around 40 soldiers have complained of symptoms including fever, persistent coughing, nausea, insomnia and migraine after shooting practice, army spokesman Per Anders Bjoerklund told AFP.
"We've started an investigation to determine the cause of these symptoms. There are different causes possible," he said.
Several leads will be explored, he said, including a new assault rifle currently being introduced to the army, the HK 416, and its ammunition made by the Finnish-Norwegian group Nammo.
The ventilation systems at the shooting ranges will also be examined.
"We're going to measure the volume of gas emitted during firing and the amount of gas inhaled by shooters," Bjoerklund said.
The HK 416 and its new ammunition are currently being used by Norwegian troops stationed in Afghanistan.
"We're going to continue to use this weapon but at the same time we're going to take precautionary measures," another spokesman, Colonel Petter Lindqvist, said, refusing to disclose further details.
Three separate reports on the illnesses have been submitted to the Norwegian military since last year.