Ilya Yashin, a leader of the Solidarity opposition movement, sent requests Monday to three law enforcement agencies, calling on them to investigate the origin of a series of compromising Internet videos targeting opposition politicians and journalists.

Under the law, violating an individual's privacy and the illegal distribution of pornography can be punished by prison terms of up to four years and up to two years, respectively.

In letters to the Prosecutor General's Office, the Investigative Committee and the Interior Ministry, Yashin asked their heads to check whether the first deputy head of the presidential administration, Vladislav Surkov, or Federal Agency for Youth Affairs chief Vasily Yakemenko were behind the videos, Yashin wrote in his LiveJournal blog.

The latest videos were released Thursday, with footage showing satirist and radio host Viktor Shenderovich; writer and Other Russia opposition movement leader Eduard Limonov; and Alexander Potkin, leader of the nationalist Movement Against Illegal Migrants, having sex with the same woman.

Shenderovich accused people from the retinue of Prime Minister Vladimir Putin of setting up the hidden-camera sting against him and others.

In March, clips featuring Yashin, independent political commentator Dmitry Oreshkin and the Russian Newsweek editor Mikhail Fishman giving bribes to traffic police were posted on the web site of the pro-Kremlin Nashi youth group.

Surkov, the Kremlin's top domestic politics guru, is widely seen as Nashi's creator, while Yakemenko was its first leader and remains a patron of the group through his post in the government.

Nashi and the government have denied involvement.

In his letters, Yashin identified the woman having sex in the videos as Yekaterina Gerasimova, whom he said works at the OrangeDisco event company in Moscow, and he called on the investigators to question her.

Yashin said he had been in a rented apartment with Gerasimova and another woman, whom he identified as Anastasia Chukova, "under similar circumstances" to those in the sex video that surfaced last week. He said it was possible he was also filmed and that the video could eventually be posted online.

Meanwhile, a Russian rock legend who has been critical of the Kremlin, DDT front man Yury Shevchuk, wrote in his LiveJournal blog on Monday that it was possible that a sex video featuring him and Gerasimova would surface.