Police took into custody Bulgaria's former Prime Minister Boyko Borissov on Thursday as part of a nationwide police operation that follows investigations by the EU prosecutor's office.

Prosecutors have opened 120 investigations into potential fraud involving EU funds.

What do we know so far?

Bulgaria's Interior Ministry said Borissov was taken into custody for 24 hours, but it did not elaborate on any possible charges against him.

A press release from the ministry said: "A large-scale law enforcement operation is underway in connection with 120 cases of the European Public Prosecutor's Office in Bulgaria."

The allegations relate to public tenders, agricultural subsidies, construction, and coronavirus recovery funds.

Local media said police had conducted searches in several cities across the country.

"Nobody is above the law," current Prime Minister Kiril Petkov said in a Facebook post.

Petkov's newly formed party won a general election in 2021, having campaigned on a "zero tolerance for corruption" platform.

Police had not commented on the reasons for the arrests, but local media reported that the cases were about the "misuse of EU aid."

Borrisov and his government have been a target for corruption allegations over the years. However, he has always denied any wrongdoing.

Also among those who were taken into custody were former Finance Minister Vladislav Goranov, the parliamentary budgetary commission chair, Menda Stoyanova, and Sevdalina Arnaudova, Borissov's media adviser.

Swift action follows EU visit

The raids immediately followed a two-day visit to Sofia by European Chief Prosecutor Laura Koevesi.

"European prosecutors have opened 120 investigations of fraud [in Bulgaria]," Koevesi said as her visit came to an end on Thursday.

"Now is the time for the relevant Bulgarian authorities to team up with us, including on particularly-sensitive cases."

Koevesi was acting on behalf of the European Public Prosecutor's Office (EPPO), which prosecutes instances of fraud against the European Union.

Both a member of NATO and the EU, Bulgaria has drawn attention from its partners amid long-standing issues with corruption, adhering to the rule of law, and preserving media freedom.

rc/msh (dpa, Reuters, AP)