KIEV, Ukraine (AP) -- Authorities in Ukraine say armed gunmen have occupied the local headquarters of the security services in an eastern city where secessionist sentiment has sparked frequent protests since the country's Russia-friendly president was ousted in February.
The Interior Ministry said Monday that groups of unidentified people erected barriers overnight on a main thoroughfare in Luhansk, which lies around 25 kilometers (15 miles) west of Russia.
Police in Luhansk said they have been put on alert and have blocked all entrances to the city.
A crowd of pro-Russian activists stormed the security services building on Sunday. Local media reported that demonstrators pelted the building with eggs, and then stones, a smoke grenade and finally a firebomb. The flames reportedly were quickly extinguished.
Ukraine's authorities have accused Russia of fomenting the unrest.