MOSCOW, November 6 - RAPSI. The Moscow Prosecutor's Office has summoned opposition activist Sergei Udaltsov, leader of the Left Front movement, to testify on November 6 as part of an investigation of the Left Front movement and any potential connection with extremism, Kommersant daily news reported, citing Udaltsov.

"The prosecutor's office has asked me to come in to testify and bring the Left Front's constitutional and financial documents with me, though we are not involved in any financial activity. I am planning to go because I have nothing to hide," Udaltsov said.

The leftist protest leader said that one of the reasons that the investigation was initiated was the organization of mass riots initiated against Udaltsov, his aide Konstantin Lebedev, and Leonid Razvozzhayev, aide to oppositionist Duma lawmaker Ilya Ponomaryov, after the TV premiere of the documentary film, "Anatomy of Protest 2." Udaltsov faces four to ten years in prison. The suspects' homes have been searched.

The filmmakers of the documentary shown on NTV, a channel owned by state-run Gazprom, claim the opposition is preparing a coup using funds from abroad. The film shows Udaltsov and his companions allegedly talking with Georgia's then- Parliamentary Defense and Security Committee head Givi Targamadze, who is said to be experienced in planning the "color" revolutions in Georgia and Ukraine, as well as mass riots in Belarus.

The film probe established that one of the voices in the scenes filmed using a hidden camera was Udaltsov's and that the meeting shown in the film took place in Minsk last June.

According to the court's ruling, Razvozzhayev and Lebedev are being held in an investigative isolation ward. Udaltsov has been released under his own recognizance.

Udaltsov said that the prosecutor's office might use the criminal prosecution against him as a reason to declare the organization extremist and then to shut it down.

According to the law, any organization planning, organizing and preparing actions aimed at seizing or appropriating powers and changing the basics of the constitutional system by force may be considered extremist.