AHMEDABAD -- Indian anti-smuggling intelligence officials have seized nearly three tons of heroin -- reportedly worth around $2.7bn -- in a major bust at a port in Gujarat state.

Forensic testing is still underway to determine the exact value of the seized drugs, officials told the BBC.

Two people have been arrested and several others are being investigated, a statement said.

The shipment originated in Afghanistan, where it was declared as talc stones.

And it was shipped to Gujarat's Mundra port from Iran.

The Directorate of Revenue Intelligence (DRI) said that it received intelligence that a shipment from the Bandar Abbas Port in Iran was suspected to contain narcotics.

It said the intelligence also revealed that the shipment was being imported by a company in the southern city of Vijaywada.

"When our officers detained the consignment and examined it, suspected narcotic drugs were recovered from the containers and the presence of heroin was confirmed," DRI said in a statement.

Officials said searches have been conducted in multiple cities across India, including the national capital, Delhi, Ahmedabad and Chennai.

"Investigations conducted so far have also revealed the involvement of Afghan nationals, who are under investigation," the agency said.