Russian federal investigators have raided the homes of several opposition activists Moscow accuses of attending seminars in Lithuania on organizing protests aimed at toppling President Vladimir Putin.

Russian Investigative Committee spokesman Vladimir Markin said investigators raided the homes of Taisia Alexandrova, Anna Kornilova and Yuri Nabutovsky on Tuesday morning, seizing computer files and other documents.

Markin says the three were among a group of Russians who went to Lithuania earlier this year for a seminar on coup techniques.

The three are being detained for questioning.

The investigation comes as part of a wider probe into a number of high-profile activists accused of plotting mass riots and a coup in an effort allegedly funded by Georgian politician Givi Targamadze.

The allegations were featured in a pro-Kremlin documentary called Anatomy of a Protest-2.

Left Front party leader Sergei Udaltsov and his assistant, Konstantin Lebedev, were among those charged with plotting crimes against the Kremlin. They face 10 years in prison if convicted.