Thousands of people were left in the dark after the incidents, although it was not clear whether they were connected.
A fire at an electrical substation on Thursday left hundreds of thousands of Puerto Ricans in the dark, soon after the power company reported a cyberattack that it was not immediately linked to the fire.
Luma Energy confirmed a fire broke out at a facility in the capital, San Juan, two hours after it said it had been targeted by a distributed denial of service (DDoS) attack that blocked customers from accessing their accounts.
“The fire caused the entire island to become quite dark,” the company said on Facebook.
Luma Energy is a new utility on a Caribbean island that will begin operations on June 1 to improve electricity transmission systems in the United States territory.
The company’s chief executive, Wayne Stansby, said about 700,000 customers were in the dark, local daily El Nuevo Dia reported. He said it would take the whole night to restore the service.
In pictures and videos posted on social media, huge flames and black smoke can be seen above the substation.
Governor Pedro Pierlusi tweeted: “All resources of the PR government are available to deal with the emergency caused by the fire at the Monasillos substation.” “Firefighters have already reached the scene.”
Pierlucci said in a later statement that state and federal law authorities were “investigating the substation explosion.”
He added that whoever is “responsible for this will be held accountable to the people of Puerto Rico”.
Officials did not say whether they were investigating a connection between the fire and the cyberattack.
Jennifer Gonzalez, who represents Puerto Rico in the US Congress, promised an investigation.
“The fire in Monasillos, the blackout for over half a million residents, the areas without lights for a week doesn’t seem like an isolated incident to me,” he said, referring to recent episodes in Puerto Rico.
“I have alerted federal law enforcement agencies to investigate each incident. They hurt people, who are victims.”
Luma Energy is jointly owned by North American parent companies ATCO and Quanta.