A Ukrainian drone strike caused a fire at a Yandex data center in Sasovo, in Russia's Ryazan region, on October 8, bringing the facility to a complete halt, the company said. A second strike hit Yandex's data center in the Kaluga region overnight on October 9, completely disabling several modules there.
Yandex said it was still assessing the damage and warned that some services may be unavailable or disrupted. "At this stage, we cannot confirm whether the equipment at our Sasovo data center can be restored," the company said on October 9.
The Sasovo site housed two of Yandex's three supercomputers used to train its artificial intelligence models, including its YandexGPT system. The company has not confirmed the condition of that equipment.
The Kaluga facility is Yandex's largest data center in Russia, covering roughly 130,000 square meters with a planned capacity of 63 megawatts and more than 3,800 server racks. Yandex said several modules there were taken out of service and that the full extent of the damage was still being evaluated.
The outages rippled far beyond Yandex itself. Users across Russia reported problems with banking services, transport websites, and online platforms, including Russian Railways, real-estate portal Cian, classifieds site Avito, telecom operator MegaFon, and T-Bank. Russian media sites and Yandex services such as mail and cloud storage were also affected.
Yandex is Russia's most widely used search engine and a core part of everyday digital life, providing maps, ride-hailing, food delivery, email, and cloud computing to tens of millions of people. The company said its data centers were "critical" to keeping those services running and that teams were working "day and night" to maintain operations, adding that it was "very difficult to predict" when the affected sites would be back online.
Ukrainian President Volodymyr Zelenskyy said the strikes were a response to recent Russian attacks on Ukrainian data centers. "We always respond in kind," he said. "Regarding data centers, as you all know, they have been and still are striking our data centers."
Yandex said none of its employees were injured in either strike. Kaluga regional governor Vladislav Shapsha said nine people were injured in drone attacks across the region, though he did not specifically comment on the data center.
What is confirmed: two of Yandex's five Russian data centers were struck within two days; the Sasovo site is fully offline; several Kaluga modules are disabled; and widespread service disruptions followed.
What remains unknown: the full extent of the damage, whether the Sasovo equipment and supercomputers can be restored, and how long disruptions to Yandex services will last. Ukraine has not formally claimed responsibility for the data center strikes, and Yandex has not issued a recovery timeline.