The eight Russians were convicted Friday and are scheduled to be sentenced Monday, RIA Novosti reported.
Charges against the activists stemmed from a May 2012 demonstration in Moscow's Bolotnaya Square, during which protesters clashed with police. The rally was one of several large-scale protests organized against Russian President Vladimir Putin's return to the presidency.
U.S. State Department spokeswoman Marie Harf issued a statement following the conviction, saying the "politically motivated trial that points to serious concerns about due process and rule of law in Russia."
"The United States continues to support the rights of all Russian citizens to exercise their fundamental freedoms, regardless of their political views," Harf said.