The capital of San Juan was left without power, as well as neighboring municipalities including Bayamón, Caguas and Carolina.

Luma Energy, which operates transmission and distribution for Puerto Rico’s power authority, said on X that the outage was tied to an issue with the power plants’ transmission lines. It provided a statement to The Associated Press saying it was investigating the outage that coincided with the shutdown of units operated by Genera PR, which operates and maintains state power generation units.

Gov. Pedro Pierluisi condemned the outage and said he was demanding answers and solutions from Luma and Genera PR.

“The events that have been occurring in recent weeks with our electrical system are unacceptable,” he posted on X. “While it is true that we have old plants and transmission lines in terrible condition, the people continue to suffer the consequences of the lack of sense of urgency that private operators are demonstrating.”

Both Luma and Genera PR were selected as private operators under Pierluisi’s administration.

The outage is the most recent in a string of blackouts to hit Puerto Rico, which is still trying to rebuild the grid after Hurricane Maria razed it in 2017 as a Category 4 storm.

The outage prompted the mayor of the San Juan capital, Miguel Romero, to declare a state of emergency late Wednesday as he accused Luma of sharing limited information about the ongoing blackouts.

“There are thousands of children with specific feeding needs, as well as older adults who often need therapy machines to protect their health and often save their lives,” the decree stated.

Scores of Puerto Ricans took to social media to condemn the most recent outage and demand the ouster of Luma, noting that it occurred amid excessive heat warnings. Not all on the island of 3.2 million people with a poverty rate of more than 40% can afford generators or solar panels.