The Narcotics Control Bureau (NCB) on Saturday claimed to have unearthed a "major" pan-India heroin trafficking network with the arrest of eight people and seizure of about 35 kg of narcotics.

The operation began on May 24 after the federal anti-drug agency first intercepted two women passengers who landed in Bengaluru from Zimbabwe and about 7 kg of heroin was seized from them, according to an NCB statement.

Their questioning led NCB officials to various other links -- a Nigerian national identified as the "kingpin" of the network and other operatives staying in Delhi and Itarsi in Madhya Pradesh.

In this operation, 34.89 kg of high-grade heroin has been seized and eight people arrested, the NCB said.

This was a major heroin trafficking network operating across the country, it said.

Out of the eight, one accused is a Nigerian and the rest are Indian nationals.

Three more women, stated to be citizens of some African nations, have been apprehended and they will be arrested once the agency gathers evidence against them, a senior officer said.

According to the statement, Rs 5.8 lakh in cash was also seized during the operation.

The Nigerian kingpin from Delhi used to ask Indian lady handlers to arrange women carriers who would fly abroad and bring drugs concealed in their luggage.

They were paid for each trip along with all travel expenses by the cartel, the NCB said.