CARACAS, Venezuela — Much of Venezuela, including the capital, Caracas, was without electricity Monday evening, as the country suffered its fourth major blackout in less than five months.

The country’s communications minister, Jorge Rodríguez, blamed “an electromagnetic attack” on Venezuela’s hydroelectric system for the power failure. He provided no details about who might have been behind the attack or how it was carried out.

A nationwide power failure in March left much of the country in darkness for over a week, collapsing basic services like public transportation and food delivery and storage.

President Nicolás Maduro accused the United States of orchestrating that power failure. “The electrical war announced and directed by the imperialist United States against our people will be defeated,” he said on Twitter