DONETSK, Ukraine (AP) — At least a dozen armed men have seized a police station in a small town in eastern Ukraine as tensions in the country’s Russia-speaking regions intensify.

The Ukrainian Interior Ministry said men in camouflage stormed a police station in Slovyansk early Saturday. The town is about 90 kilometers (55 miles) south of the regional center, Donetsk, where pro-Russian protesters have occupied a government building for nearly a week.

Masked pro-Russian activists stand after leaving a regional prosecutor's office in Donetsk, Ukraine, Saturday, April 12, 2014. Saturday morning a group of pro-Russian activists armed with metal sticks seized the office. Later they have left the building after talks with police. Nobody was arrested. (AP Photo/Efrem Lukatsky)

Masked pro-Russian activists stand after leaving a regional prosecutor’s office in Donetsk, Ukraine, Saturday, April 12, 2014. Saturday morning a group of pro-Russian activists armed with metal sticks seized the office. Later they have left the building after talks with police. Nobody was arrested. (AP Photo/Efrem Lukatsky)

Interior Minister Arsen Avakov pledged a “very tough response” to the seizure.

Video on a local website showed several armed men in balaclavas guarding the entrance to the police station.

Protesters who have held the administration building in Donetsk since Sunday initially called for a referendum on secession but later reduced the demand to a vote on autonomy within Ukraine.