Original sentence: On 15 April, the interim government in Kiev announced a counteroffensive to confront the pro-Russian militants, and on 17 April, tensions de-escalated as Russia, the US, and the EU agreed on a roadmap to defuse the Ukraine crisis
Edited sentence: On 15 April, the interim government in Kiev announced a counteroffensive to confront the pro-Russian militants, but it unraveled in disarray as an entire contingent of 21 armored vehicles surrendered.On 17 April, tensions de-escalated as Russia, the US, and the EU agreed on a roadmap to defuse the Ukraine crisis