The initial report leads one to believe that they were still at cruise altitude. No report of a request or clearance to descend. Descending normally from FL330 would only require about 120 NM (including decel). Additionally there is high terrain south of Tromso that keeps you at or above 5000ft until inside about 11 miles if landing Rwy 01 (~80% or more), so no, I don't think they were descending.