A blackout hit Havana and the rest of the western half of Cuba on Wednesday, leaving millions of people without power on an island struggling with chronic outages blamed on a crumbling electric grid. Lázaro Guerra, general director of the Ministry of Energy and Mines, said the massive outage was caused by a failure on a transmission line that connects two major plants.

The power grid was operational once again by Wednesday afternoon, but the government warned that the restoration of electricity would not be immediate and that generation deficits persisted. The nearly 12-hour blackout snarled activities in the capital and beyond.