Emergency crews in Ukraine’s Kyiv region are working tirelessly to restore electricity after repeated Russian attacks on the country’s energy infrastructure, officials reported on Wednesday.

In the town of Boryspil, home to roughly 60,000 people, workers have been dismantling and reconstructing damaged electrical systems under harsh winter conditions, with temperatures plummeting to -15 C (13 F). Teams often work from early morning until midnight, according to Yurii Bryzh, head of the Boryspil regional department of private electricity provider DTEK, who spoke to The Associated Press.

Although power has been restored for brief periods of around four hours each day, Bryzh explained that households often overwhelm the system by switching on multiple devices simultaneously to cook, wash, or charge phones, leading to repeated outages.

Kyiv Mayor Vitali Klitschko described the blackouts as the most extensive and prolonged since Russia’s full-scale invasion nearly four years ago, noting that some residents have been without electricity for several days.