Yandex has been forced to pause its operations at a data centre near Moscow after the facility was damaged in a Ukrainian drone strike - the third attack on the Russian tech giant's sites this week.
The company - dubbed "Russia's Google" - said no one was injured at the centre in Vladimir, east of the capital, but some of its services were unavailable to users.
Earlier this week, Yandex said it was struggling to maintain its services after two of its five data centres were hit in Ukrainian strikes.
Both Russia and Ukraine have stepped up attacks on infrastructure in recent months as the war between them continues in its fifth year following Russia's full-scale invasion.
Kyiv said it was targeting places that provide revenue streams for Moscow's war machine, and that the attacks could force Russia to divert its resources to repair the damage at Yandex.
Sunday's attack came hours after US President Donald Trump warned that Ukraine should "damn well stop" attacking Russia's oil refineries so Moscow could release more diesel to the global market - a deal that has drawn criticism from Europe and sparked a diplomatic row with Ukraine's President Volodymyr Zelensky.
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Yandex confirmed on Telegram that its data centre in Vladimir had been damaged and that operations had been "completely suspended", although it said it was working to restore connectivity.
The other strikes against Yandex facilities were on Thursday in Sasovo and Friday in in Kaluga, south-west of Moscow, causing problems for some of its services, such as its AI chatbot and smart home devices.
The tech company - which also runs a food-ordering and taxi app used by tens of millions of people - said at the time that its data centres were critical for the normal operation of its services, and that it was "very difficult to predict" when they would be back online.
Meanwhile, Russian strikes on Ukraine have continued through the weekend.
The State Emergency Service of Ukraine said six people were injured in Russian attacks overnight on four districts in its south-eastern Dnipropetrovsk region.
On Saturday, at least 20 people including four children were killed in Russian attacks on Zaporizhzhia, local officials confirmed.
Russia has previously also struck Ukrainian data centres, causing internet outages and prompting some firms to move their servers abroad.
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