The riot broke out on Thursday, when dozens of migrants were trying to leave the Harmanli center put into quarantine, but were met by police and firefighters who used water cannons against them. Around two thousand refugees took part in the violent protest. According to the Interior Ministry, over 400 people were detained following the riot.
"Commonly a terrorist attack happens in the places where violent clashes occur, sleeping [terror] cells are always involved [in such cases]," Borissov was quoted by the BTV broadcaster as saying.
Borissov also said that all those possibly involved in acts of vandalism would be extradited. The first extradition could take place in December, and before that, the offenders would be living in a closed camp.
Earlier this week, Bulgarian authorities decided to enforce a quarantine due to a threat that migrants may be the carriers of infectious diseases and may provoke their spread. However, after medical checks, the doctors reported that there was no danger of an outbreak of serious infectious diseases.
