A plane from Israel made an emergency landing at Sofia airport after a bomb threat arrived by email, chief commissioner Lyubomir Nikolov, acting chief secretary of the Interior Ministry, said on Tuesday, 3 November.

Officers from the Specialised Counter-Terrorism Unit are checking the plane for explosives. It landed minutes before Nikolov spoke to reporters in Pernik.

Various institutions also received bomb threats today. The messages claim that explosive devices have been planted. Nikolov said there is no information pointing to any specific terror plan or action.

"They have already started to involve some of the airlines too, and this means the plane's route has to change," he said.

The sender of yesterday's threat has not yet been identified. In similar earlier cases, the senders' email addresses were found, and their IP addresses turned out to be in other European countries, Nikolov said.

Security has been tightened at airports, and the services are on constant alert. Staff follow a set protocol for every warning, the chief commissioner said.

Police also carried out a special operation today against an organised crime group suspected of trafficking illegal migrants from the Greek border to European countries. Officers searched addresses in Sofia and Pernik. Several people were detained, but Nikolov gave no exact number and no details about them.

Nikolov was in Pernik to present a road safety initiative to pupils at St Ivan Rilski primary school.