Argentina is investigating what caused a massive power cut that hit nearly 50 million people.
President Mauricio Macri called the outage “unprecedented”, promising a thorough inquiry.
Almost all of Argentina, neighbouring Uruguay and some areas of Paraguay woke up to darkness on Sunday.
The disruption hit public transport while hospitals were forced to run on generators. Power had largely been restored by the end of the day.
Argentine officials said it began with a failure in the country’s “interconnection system” but that the exact cause was unknown.
Energy Minister Gustavo Lopetegui said it was unlikely that a cyber-attack was responsible, and that it would take 10-15 days for the results of the investigation to be published.
Despite the massive outage he said the country’s electrical network was “very robust”.