Customs officials working at the airport in the Bulgarian capital have busted an international cocaine trafficking ring.

Initially, the officials found and seized express courier shipment with cocaine concealed in a speaker, which was destined for export from Bulgaria to Israel.

During a follow-up operation on the territory of Sofia, customs officials detained two Bulgarian and two Russian citizens and seized another cocaine shipment destined for Israel.

Checks have been carried out at two hotels in Sofia where evidence of the group's criminal activity have been found.

Earlier on Thursday, technical problem with the navigational maps of an air carrier caused delay to five flights operated by Wizz Air from Sofia to London, Dortmund, Milan, Frankfurt-Hann and Brussels.

The problem has been fixed and flights from both terminals are conducted according to the schedule.

The airport officials assured that there is no threat to the security and dismissed speculations aired on media and social networks.