32 CFR §2400.34

1. (a)Foreign government information classified by a foreign government or international organization of governments shall retain its original classification designation or be assigned a United States classification designation that will ensure a degree of protection equivalent to that required by the government or organization that furnished the information. Original classification authority is not required for this purpose.
2. (b)Foreign government information that was not classified by a foreign entity but was provided with the expectation, expressed or implied, that it be held in confidence must be classified because Executive Order 12356 states a presumption of damage to the national security in the event of unauthorized disclosure of such information.