BBC News - Ukraine and pro-Russia rebels sign ceasefire deal
The timing of this seems to be a strategic maneuver to halt rebel advances before they can secure territory that will basically connect Crimea to Russia by land. Right now the only land access to Crimea is through Ukraine. Land access to Crimea through Russian friendly territory occupied by the rebels would be a great victory for pro-Russian forces.The rebels, who had largely been pushed back towards their strongholds of Donetsk and Luhansk, made new advances in recent days.
Fighting was continuing on Friday around Mariupol, a coastal city about 110km (70 miles) south of Donetsk.