Lights back on, Argentine leaders still in dark over massive power cut

Power sub-station UTE Ramon Anador is seen working partially in the neighbourhood Parque Batlle after a massive blackout in Argentina cut electricity to much of neighbouring Uruguay and swaths of Paraguay, in Montevideo, Uruguay June 16, 2019. REUTERS/Mariana Greif

BUENOS AIRES (Reuters) - The lights were back on across virtually all of Argentina and neighbours Paraguay and Uruguay on Monday morning, according to Argentine energy officials, though the cause of Sunday's massive blackout remains a mystery.

Argentina's grid collapsed early on Sunday morning, cutting power to tens of millions of people in South America, hobbling phone and internet communication regionwide and shutting down YPF SA's La Plata refinery, Argentina's largest.