US and Afghan forces seized 50 tonnes of opium and 1.8 tonnes of heroin, and killed 17 Taliban insurgents in a joint operation in southern Afghanistan today.<br/> <br/>Mohammad Zahir Azimi, Defence Ministry spokesman, told AFP in Kabul today that the drug haul, one of the biggest in recent memory, was worth five million US dollar<br/> <br/>In a five-hour operation that began at 11:00 am (1200 hrs IST), the soldiers dropped from helicopters into the Kajaki district of troubled Helmand province, source of most of the world's heroin, he said.<br/> <br/>According to their calculation, they have destroyed five million US dollar worth of drugs today the spokesman said.<br/>