At least 16 people have died in Argentina and dozens have been hospitalized after consuming cocaine suspected of containing a poisonous substance, authorities in Buenos Aires province, at the epicenter of the incident, said on Wednesday.

A spokesperson for the provincial security Minister Sergio Berni, shared a list of fatalities at hospitals in the suburban region around the country's capital city, raising the number from 12 deaths and 50 people hospitalized announced earlier.

Provincial security forces detained some people suspected of selling the drug after the first deaths occurred on Wednesday.

Some local media outlets reported that the cocaine had been "cut" with a toxic substance, likely by a drug gang looking to cut costs amid a turf war with rival groups.

"We are waiting for the laboratory results and the results of the investigations into the people who have been detained," Berni told local television.

Reuters could not immediately reach the police and courts for further information.

The local government of one affected area, Tres de Febrero, said in a statement it was aware of people being made seriously ill due to "allegedly adulterated cocaine" and was working with emergency services and hospitals to prevent more deaths.

It urged people to discard any drugs bought recently.

"If you use cocaine, we recommend that you do not use what you have bought and be aware of the possible symptoms: confusion, convulsions and loss of consciousness," it added.