New Delhi, Dec. 6 -- BRUSSELS - Kaja Kallas, the European Union's top diplomat, moved swiftly to distance herself from a burgeoning corruption scandal that has ensnared her predecessors and exposed fissures in the bloc's diplomatic apparatus. In a pointed internal memo to staff at the European External Action Service, Ms. Kallas described fraud accusations against former high-ranking officials as "deeply shocking," while emphasizing that the alleged misconduct predated her tenure. The carefully worded message, first reported by the Berliner Zeitung, has drawn criticism from some quarters as an attempt to shield her nascent leadership from the fallout of a probe that has already led to high-profile arrests and resignations.

The controvers...