OSLO, Oct 25 (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 represents a "threat to fundamental national interests" and should be expelled from Norway, deputy PST chief Hedvig Moe told Reuters, describing him as an "illegal agent".The head of the research group the man was part told Reuters the suspect arrived in Tromsoe in December 2021 as an unpaid guest researcher, which was unusual but not unheard of, who had recently completed a master's degree in Canada.According to publicly available data, his masters was from the University of Calgary's Centre for Military, Security and Strategic Studies.The arrest was made possible with the collaboration of "several" international security services, declining to say from which countries."