At least seven kg of heroin, worth Rs 35 crore, was recovered in a joint operation by the Border Security Force (BSF) and Narcotics Control Bureau (NCB) here, a BSF official said on Saturday.The heroin was in seven sealed packets."Based on a specific input, a special joint search operation was carried out in the Border Out Post area of Kakkar in the Amritsar sector in between the border fence and the International Border," BSF Deputy Inspector General R. S. Kataria said."During search, seven packets (weight about seven kg) were recovered," he said.Punjab shares a 553-km long International Border with Pakistan.