HAVANA (AP) — Millions of people in Cuba were left without electricity for two days after the nation's energy grid went down when of the island's major power plants failed. The widespread blackout that swept across the county was the worst in years.

Cuba's government blames weeks of worsening blackouts on deteriorating infrastructure, fuel shortages and rising demand.

After electricity was partially restored in Cuba following an island-wide blackout, the electrical grid collapsed a second time, causing widespread alarm. Journalist Ed Augustin told NBC News that while power is gradually being restored in some areas,

Prime minister Manuel Marrero declared an "energy emergency" on Thursday following months of lengthy blackouts.

Cuba remained without electricity Saturday as a nationwide power outage dragged on for a second day. At dawn, most neighborhoods in Havana were dark, except for hotels and hospitals with emergency generators and the very few private homes with that kind of backup in this economically challenged island nation that has grown accustomed to periodic power outages.

Cubans experienced their second black out wave Saturday after government officials said they were working to restore electrical service to hospitals and crucial service centers after a grid failure on Friday.

Cuba was plunged into darkness for a second time on Saturday after its electrical grid collapsed again hours after authorities announced they had begun re-establishing service.