The Luhansk police have been alerted, the regional police department's public relations section said on Monday.

"The traffic police have blocked the approaches to Luhansk. The search for suspected wrongdoers is underway," it said.

Protesters stormed the building of the Ukrainian Security Service's Luhansk regional department and smashed out the doors on Sunday.

The city prosecutor's office opened a criminal case on the counts of mass disturbances.

The police reported later that the protesters had seized weapons from the Ukrainian Security Service department's armory.