The Ukrainian Interior Forces in Crimea and the entire police personnel have been alerted following the seizure of the Crimean Supreme Council building in Simferopol, acting Ukrainian Interior Minister Arsen Avakov said.

"A unit of unidentified individuals armed with automatic weapons and machine guns seized the Crimean Supreme Council building in Simferopol early this morning. The Interior Forces and all police personnel have been put on alert," Avakov said on Facebook.

After that, the neighborhood where the Crimean Supreme Council is located was cordoned off, Avakov said.

"A number of other response measures have been taken in order to prevent the development of extremist actions and stop the situation from growing into an armed clash in the city center," he said.

Violetta Lisina, the Crimean prime minister's press secretary, had told Interfax earlier that a group of about 30 people had occupied the Crimean parliament and government building at about 4:30 a.m. local time on Thursday. Nobody was injured in the process, she said.