Dozens of Bulgarian schools were closed for a second day on March 28 following bomb threats with investigators saying they were looking into potential Russia-linked terror actions meant to disrupt the upcoming snap parliamentary elections scheduled for April 2.
Most of the schools targeted in the threats -- first made by e-mail and phone on March 27 -- were located in the capital, Sofia, and the Black Sea port cities of Varna and Burgas. The threats prompted the disruption of classes and the evacuation of students.
More threats were made on March 28, with Sofia's Economic University among the institutions targeted by the calls that appeared to be hoaxes after police teams searching for explosives failed to find any devices.
The Interior Ministry said it suspected Russia may be behind plans to disrupt the April vote, since most polling across Bulgaria will take place at schools, with Acting Interior Minister Ivan Demerdzhiev saying similarly worded threats had been sent to other European schools before.
"What is happening to us has been happening in many European countries recently," Demerdzhiev told the media on March 28 in the city of Malko Tarnovo in the Burgas region, adding that the ministry's investigation is taking into account a possible hybrid attack originating in Russia.
SEE ALSO: Old Coins, An Anonymous Tip, And 'Urgent Actions' Land A Bulgarian Investigative Reporter In JailDemerdzhiev said EU and U.S. partner agencies were aiding Bulgaria in its effort to pinpoint the source of the threats.
EU and NATO member Bulgaria is among the countries that imposed sanctions on Russia following its unprovoked invasion of Ukraine and has since been regarded as a hostile country by the Kremlin.
Asked about how authorities will respond if bomb threats continue through election day on April 2, Demerdzhiev said, "The election process will only be interrupted if there is a credible threat."
Demerdzhiev said authorities plan to review the procedures that assess the seriousness of a threat before evacuating public institutions.
"Within days, a change in the protocol for action in such situations will be prepared. At this stage, we have no confirmed information about the original source of the bomb threats to Bulgarian schools," said Demerdzhiev.
The Sofia City Prosecutor's Office, meanwhile, said that it had opened an investigation into a potential act of terrorism.