The Ukrainian government has given the private army of billionaire Dnepropetrovsk governor Igor Kolomoysky a day to lay down their weapons, after they occupied and erected a fence around the headquarters of the national oil company.

“We won’t have armed personal security forces of businessmen and politicians on the streets of our cities. This applies to every single one of them,” Interior Minister Arsen Avakov said on his Facebook page.

“All security forces have 24 hours to comply with the letter of the law.”

President Petro Poroshenko has also dispatched two battalions of the elite National Guard to Dnepropetrovsk, to diffuse “rising tension in the region.”

“There will be no more pocket armies for each governor. Any regional armed forces must fall in with the national military hierarchy,” the president warned.

Arriving in unmarked armored trucks, dozens of camouflaged men barricaded themselves in the head office of majority state-owned oil producer Ukrnafta in central Kiev on Sunday afternoon. Kolomoysky, whose net worth is estimated at $1.3 billion by Forbes but may be much greater, according to local sources, was inside, issuing orders to build an impromptu barrier around the office. The government says no permit has been issued to allow this.