Power outages have cut off electricity across Puerto Rico, whose residents have already endured long periods of darkness after Hurricane Maria.

The island’s power authority said it could take between 24 and 36 hours to restore electricity throughout a US territory still struggling to recover from the storm’s lasting devastation.

“The entire electrical system in Puerto Rico collapses AGAIN! Back to September 20th”, the date Maria hit, San Juan Mayor Carmen Yulín Cruz said on Twitter.

An excavator caused the blackouts by accidentally felling a transmission line, authorities told the Associated Press.

Officials said they would focus on restoring power to hospitals, airports, banking centres and water systems.

A few hours into the blackout, power was back on at a half-dozen hospitals and medical centres. The main airport in San Juan remained open thanks to backup generators.

Bringing aid to Puerto Rico Show all 20 1 /20 Bringing aid to Puerto Rico Bringing aid to Puerto Rico Crew chief Kenney shelters under the blade of an HH-60 Blackhawk helicopter from 101st Airborne Division's "Dustoff" unit preparing to take off during recovery efforts following Hurricane Maria, in Isla Grande, Puerto Rico, October 6, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico An HH-60 Blackhawk helicopter from 101st Airborne Division's "Dustoff" unit takes off behind Crew Chief Alexander Blake and his fellow soldiers during recovery efforts following Hurricane Maria, in Morovis, October 5, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Crew member Bynum stands in tropical rain as a HH-60 Blackhawk helicopter from 101st Airborne Division's "Dustoff" unit prepares to take off during recovery efforts following Hurricane Maria, in Isla Grande, October 6, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico UH-60 Blackhawk helicopter pilot Chris Greenway receives a hug from a woman thanking him for water as he works with the First Armored Division's Combat Aviation Brigade during recovery efforts following Hurricane Maria, in Verde de Comerio, October 7, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico A man carries a case of water away from an HH-60 Blackhawk helicopter after soldiers working with 101st Airborne Division's "Dustoff" unit dropped off relief supplies during recovery efforts following Hurricane Maria, in Jayuya, October 5, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Crew chief Alexander Blake from 101st Airborne Division's "Dustoff" unit loads water into a helicopter during recovery efforts following Hurricane Maria, in Isla Grande, October 5, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Residents wait for soldiers in UH-60 Blackhawk helicopters from the First Armored Division's Combat Aviation Brigade to deliver food and water during recovery efforts following Hurricane Maria, in San Lorenzo Reuters Bringing aid to Puerto Rico An HH-60 Blackhawk helicopter from 101st Airborne Division's "Dustoff" unit lands in a field to avoid lightning during recovery efforts following Hurricane Maria, in Manati, October 5, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Residents hold their hands aloft to signal that they need water as UH-60 Blackhawk helicopters from the First Armored Division's Combat Aviation Brigade fly past during recovery efforts following Hurricane Maria, near Ciales, October 7, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Tropical rain splashes on a runway as HH-60 Blackhawk helicopters from 101st Airborne Division's "Dustoff" unit wait for weather to clear during recovery efforts following Hurricane Maria, in Isla Grande, October 6, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Pilot Eldwin Bocanegra Torres speaks with residents isolated by landslides in the mountains after unloading water and food from a helicopter during recovery efforts following Hurricane Maria, near Utuado, October 10, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Residents stand in front of wind-damaged trees as they wait for soldiers in UH-60 Blackhawk helicopters from the First Armored Division's Combat Aviation Brigade to deliver food and water during recovery efforts following Hurricane Maria, in San Lorenzo, October 7, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico The contents of a home are seen from the air during recovery efforts following Hurricane Maria near Utuado, October 10, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Thomas looks out of the window of an HH-60 Blackhawk helicopter from 101st Airborne Division's "Dustoff" unit, loaded with relief supplies, during recovery efforts following Hurricane Maria in Isla Grande, October 6, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico A message written on the rooftop is seen from the air during recovery efforts following Hurricane Maria near Humacao, October 10, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico A HH-60 Blackhawk helicopter from 101st Airborne Division's "Dustoff" unit lands in a field during recovery efforts following Hurricane Maria in San Sebastian, October 6, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Sergeant First Class Eladio Tirado, who is from Puerto Rico, looks for a landing spot for a UH-60 Blackhawk helicopter from the First Armored Division's Combat Aviation Brigade, during recovery efforts following Hurricane Maria near Ciales, October 7, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Boys carry water away from an HH-60 Blackhawk helicopter after soldiers working with the U.S. Army's 101st Airborne Division's "Dustoff" unit dropped off relief supplies during recovery efforts following Hurricane Maria, in Jayuya, October 5, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Sergeant First Class Eladio Tirado from the First Armored Division's Combat Aviation Brigade, who is from Puerto Rico, speaks with residents as he helps during recovery efforts following Hurricane Maria, in San Lorenzo, October 7, 2017 Reuters/Lucas Jackson Bringing aid to Puerto Rico Residents peek through a fence at helicopters from 101st Airborne Division's "Dustoff" unit that had parked in a locked field during recovery efforts following Hurricane Maria, in Lares, October 6, 2017 Reuters/Lucas Jackson

The outages were not expected to affect a Major League Baseball game scheduled to be played in San Juan, the capital, between the Minnesota Twins and the Cleveland Indians, whose star Puerto Rican shortstop Francisco Lindor brought a moment of joy to fans last night.

“The game will GO ON. Nothing will stop us”, Ms Cruz said.

Schoolkids scream with joy as electricity returns to their school in Puerto Rico

Millions of residents were plunged into darkness after Maria pummelled Puerto Rico in September, inflicting severe damage on its electric grid.

As the latest power outage demonstrated, efforts to restore the island’s infrastructure have been halting in the seven months since Maria made landfall. Last week, a tree toppled into a power line and wiped out service for some 870,000 customers.

Critics have accused the Trump administration of doing too little to aid the struggling territory. Senate minority leader Chuck Schumer, a New York Democrat, called the latest outage “unacceptable”.