Ukrainian President Petro Poroshenko has said it is impossible to win the conflict in the east by force alone, but also warned that his military would deal a "crushing defeat" to pro-Russian rebels if they tried to advance in violation of the ceasefire.
Russia's War Against Ukraine
Al Jazeera: Poroshenko vows crushing defeat of rebels
Ukrainian President Petro Poroshenko speaking to servicemen of the Ukrainian Army during a meeting in the airport of Mariupol on Sept. 8.
