MILAN (AP) — Italian authorities say they have seized 24 million tablets of an opioid painkiller that were bound for Libya and which international narcotics experts suspect the Islamic State group has been selling and giving its fighters.

Italian financial police said Friday that the shipment of the drug tramadol was en route from India to Libya when it was seized in the southern Calabria region. The interception came six months after authorities in Genoa seized another shipment of 37 million tablets.

Prosecutors in Italy said the Islamic State group traffics tramadol to help finance its operations.

They say the painkiller also has been nicknamed "the drug of fighters" for its well-documented use by jihadist fights in the Middle East "both as an excitant and to increase the capacity for physical force."