Caracas and 20 of the country’s 23 regions were initially left without electricity on March 7. The National Electric Company said the blackout had been caused by an accident at the Simon Bolivar Hydroelectric Plant, which Venezuelan President Nicolas Maduro blamed on "US imperialism." However, the US Department of State denied any involvement. Electricity began to be gradually restored across Venezuela on March 8 but the situation worsened on March 9 following reports about an explosion at an electric substation located on the outskirts of the city of Ciudad Bolivar. Due to the blackout, the Venezuelan government declared March 11 a day off.