Cuba reconnected its national electrical grid and restored power to the majority of the capital Havana by late on Sunday,energy officials said,nearly two days after an island-wide outage knocked out power to 10 million people.

Havana´s electric company said late on Sunday that approximately two-thirds of its clients in the city had seen power restored and said that number would increase overnight.

Cheers could be heard in neighborhoods across the city as the lights flickered on after two days without electricity.

Cuba's grid collapsed on Friday evening after a transmission line at a substation in Havana shorted,beginning a chain reaction that completely shut down power generation across the island.

Most of Havana-densely populated and a major tourism center-had gone without power since then,paralyzing commerce,shutting down most restaurants and blacking out street and stoplights across the city of two million people.

The grid operator said the country's two largest oil-fired power plants,Felton and Antonio Guiteras,were back online and generating electricity by late Sunday,a major benchmark for restoring power across the island.

Electricity had also arrived in the country's westernmost Pinar del Rio province,the last to see power restored,just before dark on Sunday,officials said.

Friday's grid collapse marked the Caribbean island's fourth nationwide blackout since October.

Cuba's oil-fired power plants,already obsolete and struggling to keep the lights on,reached a full crisis last year as oil imports from Venezuela,Russia and Mexico dwindled.

Even before Friday´s grid collapse,many across the island had already been experiencing daily blackouts that reached 20 hours or more.

Though Cuba had made progress restoring electricity on Sunday,officials said they were generating just one-third of typical daily demand,leaving many residents still in the dark.

Schools in Pinar del Río,Artemisa and Mayabeque provinces in western Cuba would remain closed until Tuesday to assure adequate conditions for students,the education ministry said.

Cuba blames the country's mounting energy crisis on a Cold War-era U.S.trade embargo and fresh restrictions from U.S.President Donald Trump,who recently tightened sanctions on the communist-run government and vowed to restore a"tough"policy toward the long-time U.S.foe.

The government is pushing to develop large solar farms with help from China in a bid to reduce dependence on antiquated oil-fired generation.