A blackout hit the western half of Cuba on Wednesday, leaving millions of people in Havana and beyond without power in the latest outage to affect an island struggling with dwindling oil reserves and a crumbling electric grid.

The government’s Electric Union confirmed the outage on social media, saying it affected people from the eastern town of Pinar del Rio to the central town of Camaguey.

The agency said crews were working to restore power and posted a picture of Prime Minister Manuel M