Power Machines is controlled by Russian steel tycoon Alexei Mordashov and has a joint venture with Germany's Siemens which has come under scrutiny because of a disputed turbine delivery to Crimea.

No charges have been brought against Roman Filippov, the CEO of Power Machines, yet, TASS reported. It was not immediately clear if his detention was linked to the Crimea turbine affair.

Interfax news agency cited an unidentified source as saying Filippov was questioned as part of a criminal case into the dissemination of a state secret and released.

Power Machines and a spokeswoman for Mordashov declined to comment. Filippov's mobile phones were switched off when Reuters tried to reach him on Thursday night.

(Reporting by Polina Devitt and Anastasia Lyrchikova; Writing by Maria Kiselyova; Editing by Chris Reese)