By Terje Solsvik and Gwladys Fouche OSLO (Reuters) -Norwegian police on Monday arrested a suspected Russian spy in the Arctic town of Tromsoe, the PST security service said on Tuesday, describing him as a rare illegal agent. The man, who worked as a researcher at the University of Tromsoe, had posed as a Brazilian citizen but police believe his real identity to be Russian. The news was first reported by Norwegian broadcaster NRK. The man represents a “threat to fundamental national interests” and should be expelled from Norway, deputy PST chief Hedvig Moe told Reuters, describing him as an “il…