Turkish media reported that the narcotics had been stashed in the floor of the apartment.

The Iranian national who rented the flat, located in Esenyurt, west Istanbul, is still at large. His name has not been officially confirmed.

The police put the huge haul of seized drugs on show to the public, laying out 42 loose bags of powdered heroin in front of piles of packages of the drug stacked against a wall.

While Turkish press outlets claim that the drugs are valued at around US$ 3.4 million in Turkey, the same quantity of heroin would fetch a much higher price if it ever reached western markets.

In the United Kingdom, its street value would be between US$ 17 and 39 million, according to data from the United Nations Office on Drugs and Crime’s World Drug Report 2014.

A major link in a historical drug smuggling route, Turkey remains a key trade center for heroin and cannabis traffickers. Narcotics produced in Afghanistan and Iran pass through Turkey on their way to reach western consumers.