Gazprom guards
from Edward Lucas' The New Cold War:
The Kremlin has given Gazprom, a private company, the unusual right to recruit and operate its own military forces to protect its overseas pipelines[p.221]
'overseas pipelines' includes Nord Stream, the planned baltic pipeline bringing Russian gas to Germany and the rest of Europe. [Lucas has much analysis of this pipeline: its expense, its unpopularity with the Baltic states, how it will enable Russia to deny gas to Eastern Europe while feeding it through to Germany. All best taken with a pinch of salt, though, given the book's unremittingly anti-Russian tone]
Lucas's source is The Times, July 2007. There are plenty of other articles about it online, but they mostly seem to be regurgitating the same few facts.