The global credit crisis is threatening to undermine the stability of the banking systems of Sweden and Norway, bringing to an end a period in which they have managed to escape the effects of the downturn virtually unscathed.

Central banks of both countries on Tuesday released quarterly financial stability reports that eschewed their usual diplomatic language and voiced concern at the possible impact of global events on their banking systems. “The turmoil has ... spread to new assets, markets and participants. The uncertainty ... will probably persist for a long time to come. It cannot be ruled out that problems will get worse,” said Stefan Ingves, governor of the Riksbank, Sweden’s central bank.