Pakistan authorities have seized nearly 6 kilograms of heroin arresting two Pakistani nationals from the airport in Karachi, anti-narcotics officials said on Friday. The arrested men are residents of northwestern city of Peshawar and Jhelum in the Punjab province. The heroin, worth millions of rupees in the international market, was being smuggled to two African countries Ghana and Ethiopia via Dubai, a statement from the anti-narcotics force office said.