"Last night, the Ukrainian side captured assets of the Donetsk water filtering station and opened fire at our positions in an act of provocation and in violation of all accords and commitments," Basurin told reporters in Donetsk.
He blamed Ukrainian forces for using the location to fire mortars and heavy machine guns at the nearby city of Yasynuvata and the village of Spartak to the northeast of Donetsk, the regional capital. Basurin said both militia positions and residential areas came under attack.
Eastern Ukraine has been torn by a conflict between the government in Kiev and local pro-independence militias since 2014. The United Nations estimates 10,000 civilians and military personnel have died in clashes, which escalated last month.