While we are awaiting an answer, you may find these answers to be of some use -

JFK was assassinated on Nov 22, 1963. The United States reeled in shock at the event. What was the reaction on the other side of the Cold War in the USSR? by u/lets_get_historical.

How did Russia/USSR act in the aftermath of the JFK assassination? Did they send condolences? by u/davepx

Did the KGB files say anything about JFK's assassination? by u/DaveyGee16