Multiple cities in Ukraine are experience power outages due to the ongoing invasion by Russian forces that started last week.
Global internet access tracker NetBlocks shared data showing widespread internet outages across Mariupol, Sumy, and other regions of the country following an increase in bombing campaigns and rocket fire launched by Russian units.
"Mariupol and Sumy are the main outage incidents we're tracking today. Overall, at national level, observable connectivity is down some 20% compared to ordinary levels prior to the onset of conflict," Alp Toker, director of NetBlocks, told ZDNet.
"The reduction in connectivity is attributed to power outages and the destruction of infrastructure in most of the major conflict zones, and the figure also reflects population flight as people leave home and shutter businesses."
Mariupol, which had about 400,000 residents before the invasion, began seeing widespread outages on Wednesday. Residents told the BBC that there has been "a relentless barrage of Russian shelling."
One resident said he has spent two days without light, heat, or water after filling up a bathtub before the water was shut off. They are now running out of food and medicine.
The outages in Sumy began on Thursday. Netblocks and others wrote that residents were reporting massive blasts at the thermal power plant and electrical substation that they said "turned the sky 'yellow and red' for miles." The town had about one million residents before the invasion began.
"The incident marks the largest single region-wide disruption to telecoms service since the onset of the conflict, and is attributed to the destruction of the region's electricity production and transmission infrastructure," Netblocks explained.
TVUA 24 editor-in-chief Olha Konsevych confirmed on Twitter that two explosions damaged the CHP plant and the electrical substation.
"Residents say they have been left without heat, water, and electricity," Konsevych said.
A number of Ukrainians on Twitter confirmed the outages, noting that they or their family members were trying to figure out what to do without electricity.
NetBlocks has also reported internet outages in other major Ukrainian cities such as Kyiv and Kharkiv. Tesla CEO Elon Musk has tried to help Ukrainians dealing with internet outages by sending Starlink terminals and making the Starlink service active in the country.