Dozens of armed men have seized the regional government administration building and parliament in Ukraine's southern Crimea region, where pro-Russian demonstrators have faced off against rival protesters.

According to the press secretary to the head of the region, Some 50 gunmen are occupying the buildings in the city of Simferopol since early morning, reports CNN.

A Russian flag is flying over the parliament building, said Violetta Limona, press secretary to Crimea premier Anatolii Mohyliov.

She added parliament and government employees were told to stay away from the buildings as Mohyliov tried to negotate with the gunmen.

The men, however, refused to listen, saying he didn't have the authority, said Refat Chubarov, a member of the Crimean Parliament.

Ukrainian Interior Minister Arsen Avakov said he has ordered police in the country to be prepared.

"Order has been issued to create a cordon around the Parliament in Crimea, and to avoid shooting and violence," he posted on his Facebook page.