Four of six camels sliced open by Iranian police contained a total of 18 kilograms of opium.
The camels were slaughtered in the central city of Nain, after being found in the back of a lorry which had been stopped. The driver was arrested.
Iran is a chief thoroughfare for narcotics in the world, with 25 percent of opium seizures worldwide occurring there. A network of forts and ramparts is forcing drug dealers to rely on more traditional smuggling methods.