Pro-Russian rebels released dozens of captive Ukrainian troops Sunday as part of a ceasefire deal . Ukrainian President Petro Poroshenko said in a Twitter post that 73 troops were released in Donetsk . But despite the ceasefire , violence continued to flare in the volatile region . As shelling rocked the city throughout the day Sunday , local officials described the situation as `` critical . '' Six civilians died and 15 were injured as the result of shelling , Donetsk 's city office said on Monday . Poroshenko spoke with German Chancellor Angela Merkel over concerns that the ceasefire deal -- brokered earlier this month -- is being violated . They `` agreed to make further efforts to settle the situation peacefully , '' Poroshenko 's office said in a statement . In an interview with TV Tsentr pm Saturday , Russian Foreign Minister Sergey Lavrov said the truce agreed upon in Minsk , Belarus , appeared to be holding generally and that Moscow , at least , is ready to work toward a long-term peace . `` Sporadic exchanges of fire occur on both sides , but the process of establishing ( a ) durable peace is still in progress , '' he said , according to parts of that interview published by the state-run Itar-Tass news agency . Which Russian companies have been hit ?
Shelling kills 6 civilians in Donetsk , city officials say . 73 Ukrainian troops are released by pro-Russian rebels in Donetsk . - The United States and the European Union impose sanctions on Russia over its actions in Ukraine. As shelling continues , officials in Donetsk describe the situation as `` critical ''