Russian tech giant Yandex's data center in Sasovo burned out from the inside, a Ukrainian OSINT analyst wrote on 22 October. On cloud-free satellite images, he saw almost no significant holes in its roof. Ukrainian drones hit the site overnight on 8 October.

Sasovo was the first strike on a data center in Russia. It came two weeks after Russia destroyed data centers in Kyiv. Drones then hit Yandex sites in Vladimir and Kaluga, a Sber data center, and a VK data center near St. Petersburg, which VK acknowledged. In occupied Donbas, monitoring channels reported hits on buildings housing telecom operators.

What the analyst sees

The analyst, who goes by Harbuz, runs the Ukrainian OSINT channel Dnipro Osint. His roof reading comes from the images. His interior claim comes from what he called available information: he wrote that a fire broke out inside and put part of the equipment out of action.

In an earlier post, Harbuz wrote that a third of the data center had burned out. In the new one, he writes that the building burned out from the inside. He does not say whether he revised the earlier figure.

Russian outlet Agentstvo studied Airbus images from 12 October. It found damage on about a third of the building. Unlike Harbuz, though, Agentstvo described a blackened western roof with damage resembling holes.

What Yandex says

On 8 October, Yandex stated that the attack caused a fire and forced it to suspend operations at the site, which hosts tens of thousands of servers, Reuters reported. Yandex Cloud and the Disk and Documents services that run on it ran with major disruptions that morning, Russian outlet The Bell reported.

Later that day, the company stated: "The scale of the damage to the infrastructure is still being assessed. For the moment, we cannot confirm whether it is possible to restore the data centre equipment in Sasovo." Two of Yandex's three supercomputers, used to develop its AI model, are housed there.

The same day, journalists asked Ukrainian President Volodymyr Zelenskyy whether Ukraine was targeting Russian data centers. He did not refer specifically to the Yandex strike, Reuters noted, but said: "We always respond in mirror-like fashion."