By Guy Faulconbridge LONDON (Reuters) – Russian mercenaries with ties to Moscow’s spies have increased their presence in Ukraine in recent weeks, stoking fears among some NATO members that Russia could try to engineer a pretext for an invasion, three senior Western security sources said. They said their concerns had strengthened in recent weeks that a Russian incursion into Ukraine could be preceded by an information war, and cyber attacks on Ukraine’s critical infrastructure such as electricity and gas networks. Russia could also use the mercenaries to sow discord and paralyse Ukraine through…
