Moody's Investors Service late Monday lowered its outlook on top-rated Germany, the Netherlands and Luxembourg to negative from stable, citing increasing uncertainties about the euro debt crisis as a whole.

The rating agency said its decision is also based on the growing risk of a Greek exit from the euro, which would set off "a chain of financial sector shocks" and it is the single currency's top-rated states who are going to share the burden of support.

In the meantime, Moody's affirmed Finland's AAA rating and stable outlook, citing the country's small and domestically oriented banking system and its limited trade links with the rest of the euro area.