Russian authorities have opened a third criminal investigation into prominent opposition and anti-Kremlin blogger Alexei Navalny.

The government's Investigative Committee said Monday that Navalny is suspected of defrauding a a liberal political party of $3.4 million.

The new charges come less than a week after Navalny and his brother were charged with defrauding a mail transport company of $1.8 million. The 36-year-old lawyer and protest organizer also faces up to 10 years imprisonment on separate charges of theft from a state-owned timber company.

Navalny has denied the charges, calling them a politically motivated attempt to stop his opposition activities.