By David Shepardson WASHINGTON (Reuters) – The parent company of a small Montana wireless carrier will pay a $600,000 fine and ensure that any ownership interests by Russian investors is divested, a U.S. agency said on Thursday. The Federal Communications Commission (FCC) in April said Truphone, the owner of Montana-based iSmart Mobile, had been indirectly controlled by Russian oligarchs since at least 2011. Under the settlement, London-based Truphone will ensure that any stake held by Alexander Abramov, Alexander Frolov or Roman Abramovich will be divested, the FCC said. The FCC had proposed …