MOSCOW, April 16 - RAPSI. Moscow's Khamovnichesky District Court rescheduled on Monday until April 19 its hearing of a lawsuit to declare self-exiled oligarch Boris Berezovskys letter extremist.

The letter was posted on the Echo of Moscow radio station's website.

The session was adjourned due to the plaintiffs absence and the need for additional information.

Andrei Khodorchenkov, the website's chief editor, told journalists that the "quoted blog letter" was published in full conformity with regulations.

The United Russia party complained to the communications watchdog and the prosecutors office about the letter and asked to see the radio station's compliance check, alleging that the letter was extremist.

United Russia said Berezovsky's letter contained calls to frustrate the March 4 presidential elections and violently overthrow the government. The ruling party maintained that Echo of Moscow violated the law on mass media by publishing extremist materials.

In turn, Alexei Venediktov, the chief editor of the radio station, said earlier that he saw no calls for a violent change to the established political setup, but as some listeners did, he removed the letter from the website and referred to the stations "lawyers for a deeper analysis."