Thousands of people have been left in the dark as a result of the incidents, although it is not clear if they were related.
A fire at an electrical substation left hundreds of thousands of Puerto Ricans in the dark on Thursday, shortly after the power company reported a cyberattack it did not immediately link to the blaze.
Luma Energy confirmed a fire at a facility in the capital, San Juan, two hours after saying it was the target of a distributed denial of service (DDoS) attack that blocked customers from accessing to their accounts.
“The fire caused major power cuts across the island,” the company said on Facebook.
Luma Energy is a new utility on the Caribbean island, which began operations on June 1 to improve the electricity transmission system in the United States.
Company chief executive Wayne Stensby said about 700,000 customers were in the dark, local daily El Nuevo Dia reported. He added that it would take all night to restore service.
Photos and videos posted on social media showed large flames and black smoke above the substation.
“All the resources of the PR government are available to manage the emergency caused by the fire at the Monacillos substation,” Governor Pedro Pierluisi tweeted. “The firefighters have already arrived on the scene.
Pierluisi said in a subsequent statement that state and federal legislative authorities “were investigating the substation explosion.”
He added that whoever was “responsible will be held accountable to the people of Puerto Rico”.
Officials did not say whether they were investigating a link between the fire and the cyber attack.
Jenniffer Gonzalez, who represents Puerto Rico in the US Congress, has promised an investigation.
“The Monacillos fire, the blackout of more than half a million inhabitants, areas without light for a week do not seem to me to be isolated events,” she said, referring to to recent episodes in Puerto Rico.
“I alerted federal law enforcement agencies to investigate every occurrence. They hurt the people, who are the sufferers.
Luma Energy is jointly owned by North American parent companies ATCO and Quanta.