A total of 14 people have been detained in the specialized operation carried out at the Bulgarian road transport administration agency on Wednesday, the Chief Prosecutor's Office has said.

Earlier Tsvetelin Tsvetanov, who heads the agency, was detained in Sofia, along with other people in the capital, but also in Vratsa and Vidin in a country-wide operation.

"[The arrests] are in relation to corruption practices at the Road Transport Administration Executive Agency and at its territorial directorates," the Chief Prosecutor's spokesperson, Rumyana Arnaudova, has told the Bulgarian National Radio.

More details on the operation carried out by the Ministry of Interior's chief directorate for combating organized crime are to be revealed on Thursday afternoon, Arnaudova has added.

Chief Prosecutor Sotir Tsatsarov has said himself he expects "at least half" of those detained will be indictedd, and has promised that further details will be revealed in the afternoon.

Specialized surveillance equipment was used during the investigation which involved the work of prosecutors and the domestic security agency DANS.

Unofficial reports link the arrests to suspected offences in issuing certificates to road transport companies as well as driving licences, but also to suspected cases of extortion, bribery and document forgery.