Russian search giant Yandex has had its Kiev and Odessa offices raided by Ukraine’s State Security Service (SBU).
The raids were part of a treason investigation seeking to discover whether Ukrainian users’ data had been illegally collected and distributed to Russian security agencies.
Yandex, which says it has 11 million users in Ukraine, denies doing so.
The Ukrainian President, Petro Poroshenko, announced sanctions against the firm earlier this month.
He said Ukrainian ISPs should stop providing access to Yandex and other Russian services.
On 29 May, the SBU released a statement accusing the company of transmitting Ukrainians’ personal data – including addresses, phone numbers and emails – to Russia.
“The information was passed to the [Russian Federation] special services for planning, organisation and conducting of intelligence, subversive, informational operations in our country against [the] sovereignty of Ukraine, [its] territorial integrity and inviolability,” the statement said.
Yandex confirmed in a statement that its offices had been raided.
“SBU is accusing management and employees of Yandex.Ukraine of gathering personal data of Ukrainian users and transmitting it to Russian security forces,” it said.
“Neither our employees in Ukraine nor management of Yandex. Ukraine have access to personal data of Yandex users.”
It added that the company had “always fiercely protected” users’ data privacy: “The allegations that our employees were transmitting personal data to Russian security forces have no merit.”
In a separate case in 2011, Yandex confirmed that it had passed confidential data to Russia’s state security service, the FSB.