MANILA, May 15, 2026 (BSS/AFP) - Widespread power cuts struck the Philippines Friday, leaving millions without electricity in the tropical nation's hottest month of the year.

The National Grid Corporation of the Philippines (NGCP) said rolling one-hour power outages hit parts of the capital Manila and the rest of the main island of Luzon from mid-afternoon.

These were due to "major grid disruptions" that affected transmission lines, as well as a maintenance shutdown of several major power plants, the NGCP and the Department of Energy said.

The disruptions are scheduled to spread to the central islands, leading to seven-hour power cuts, NGCP said.

"The public deserves a complete accounting of incidents of this magnitude," Energy Secretary Sharon Garin said in a statement.

"We will ensure that all operational, technical, and compliance dimensions are fully examined and that appropriate actions are taken where warranted," she added.

Garin did not say when the power supply will return to normal.

Luzon accounts for almost half of the Philippine population of 116 million, as well as economic output.

The outages are occurring in the hottest month of the year, when demand for air conditioning ramps up.

The power cuts occurred even though Philippine government agencies are observing a four-day work week, imposed shortly after the start of the Iran-US-Israel war.