BUENOS AIRES, Argentina: Some 20 people died and 74 were hospitalized after using adulterated cocaine in Buenos Aires, Argentina, authorities have said.

The victims, who come from the Hurlingham, Tres de Febrero and San Martn districts of the capital region, were removed for treatment in ten local hospitals.

They were believed to have suffered convulsions and sudden heart attacks.

Investigators believe the illegal drug was either “cut” with another substance or laced with poison, while the regional security minister called on users to dispose of cocaine bought in the past 24 hours.

The drugs were bought in the same shanty town where nine arrests have been made, according to reports. Investigators are awaiting the results of post-mortem examinations to compare drugs seized in raids, with those consumed by the victims.

Local media reported an empty police car was attacked and damaged by people related to one of the victims outside a hospital in Hurlingham.

A 2019 report on drug consumption in the Americas listed Argentina as the country with the third highest rate of cocaine consumption per capita, after the U.S. and Uruguay.

The Buenos Aires Times said that police in San Martin have identified four of the victims as Hernan Castro, 45, Martin Lopez, 36, Dino Melgarejo, 33, and Fernando Yacante, whose age was not given.

Raids were launched after one user reportedly told police they had bought cocaine from an individual in the Puerta 8 shantytown in Tres de Febrero.

“Every dealer that buys cocaine cuts it. Some do it with non-toxic substances, such as starch. Others put hallucinogens, and if there is no form of control, those things pass,” said Sergio Berni, security minister for Buenos Aires province, as quoted by local media.

Another official, San Martin attorney-general Marcelo Lapargo, said, “This event is exceptional. We have no precedent.”