Russian guards in Tajikistan have seized more than a tonne of heroin from neighbouring Afghanistan in the biggest drugs haul intercepted on the border, the guards said on Friday. Prosecutors also arrested the head of the Tajik drugs control agency on unspecified charges, although there was no immediate indication the two incidents were linked. Afghan opiate drugs flow into Russia via vast but sparsely populated Central Asia and then on to western Europe. In the West, the latest stash could have fetched up to $300 million. A spokesman for the guards said they found 1,009 kg (2,220 lb) of heroin and 72 kg of opium on Thursday by the Pyandzh river, which follows the border. The record haul doubled this year's heroin seizures by Russian border guards. The Russian success comes after a recent spat between Russia and Tajikistan, who both independently combat drugs smuggling in the country, about the presence of the Russian border guards. Russia keeps thousands of border guards and other troops in Tajikistan, who help safeguard the peace after a 1992-97 civil war and patrol most of the mountainous Afghan border.