KIEV, Ukraine — Ukraine's security service says it has detained a 15-strong armed gang planning to seize power in an eastern province on the border with Russia.

The Security Service of Ukraine said Saturday that it seized 300 machine guns, an antitank grenade launcher, a large number of grenades, five handguns and petrol bombs.

It said the group intended to mount a grab for power in the Luhansk province on April 10 by sowing panic among the local population. No names or additional details were provided.

Luhansk and neighboring mainly Russian-speaking eastern provinces have seen active calls for separatism following February's toppling of President Viktor Yanukovych. Ukraine's pro-European interim government accuses Russia of fomenting secessionist sentiments.

The Crimean Peninsula was annexed by Russia last month following a contentious referendum.