Former EU foreign policy chief Federica Mogherini and two others have been formally accused of procurement fraud and corruption, conflict of interest and violation of professional secrecy, the European Public Prosecutor's Office said.
The three individuals were detained as part of an EU fraud investigation and have now been released while the investigation is ongoing, EPPO said, adding they were not considered a flight risk.
EPPO referred to the other two suspects as a senior staff member at the College of Europe in Bruges and a senior official from the European Commission.
Three sources told Reuters that one of the detainees was senior EU diplomat Stefano Sannino.
Neither Ms Mogherini nor Mr Sannino could be reached for comment.
"All persons are presumed innocent until proven guilty by the competent Belgian courts of law," EPPO said.
Their arrests followed raids at the EU's diplomatic service in Brussels, at the College of Europe - an elite university in Bruges that educates many EU officials - and at the houses of suspects.
Ms Mogherini was the EU's high representative for foreign and security policy and head of its diplomatic service from 2014 to 2019.
She became rector of the College of Europe in 2020.
According to EPPO, the investigation concerns "suspected fraud related to EU-funded training for junior diplomats".
Ms Mogherini and Mr Sannino, both Italian nationals, are well known in Brussels diplomatic circles, and news of their detentions sent shockwaves through the EU community.
