When Nokia Pulled Out of Russia, a Vast Surveillance System Remained

Nokia said this month that it would stop its sales in Russia and denounced the invasion of Ukraine. But the Finnish company didnt mention what it was leaving behind: equipment and software connecting the governments most powerful tool for digital surveillance to the nations largest telecommunications network.

The tool was used to track supporters of the Russian opposition leader Aleksei A. Navalny. Investigators said it had intercepted the phone calls of a Kremlin foe who was later assassinated. Called the System for Operative Investigative Activities, or SORM, it is also most likely being employed at this moment as President Vladimir V. Putin culls and silences antiwar voices inside Russia.

For more than five years, Nokia provided equipment and services to link SORM to Russias largest telecom service provider, MTS, according to company documents obtained by The New York Times. While Nokia does not make the tech that intercepts communications, the documents lay out how it worked with state-linked Russian companies to plan, streamline and troubleshoot the SORM systems connection to the MTS network. Russias main intelligence service, the F.S.B., uses SORM to listen in on phone conversations, intercept emails and text messages, and track other internet communications.

The documents, spanning 2008 to 2017, show in previously unreported detail that Nokia knew it was enabling a Russian surveillance system. The work was essential for Nokia to do business in Russia, where it had become a top supplier of equipment and services to various telecommunications customers to help their networks function. The business yielded hundreds of millions of dollars in annual revenue, even as Mr. Putin became more belligerent abroad and more controlling at home.