There probably is an amount of Eastern European gangsters, but as far as ''taking over'' anything...not very likely. Groups such as the REAL IRA (which has become more of an organized crime group than a terrorist organization) are as ruthless as vicious as the ''Russian'' groups and wouldn't let them take over anything.
As you said, they are both ruthless and vicious, if there was some taking over, then it'd be an open warzone there and we'd hear about it. Most likely they are working together and the media are making an elephant out of a fly as always.
