Also, physical assault against diplomats is quite a bridge to cross. The Russians are known to harass diplomats, but not in this way -
> Russian intruders had broken into their homes late at night, only to rearrange the furniture or turn on all the lights and televisions, and then leave. One diplomat reported that an intruder had defecated on his living room carpet.
Also, the Russians physically assaulted U.S. embassy personnel who were CIA under diplomatic cover. Right after 9/11, the CIA was on a heavy recruiting campaign so they gave permission for some former agents to tell some (general) stories. The CIA agent who first made contact with Victor Shemov, then a professor at Texas A&M, told us the story of that night. He had to shake his four man KGB tail, don a disguise, and meet Shemov. When he returned to the U.S. embassy, the KGB intercepted him and beat him to a pulp.