NEW : Ukrainian President 's office : Cease - fire is in 72 hours . Ukraine 's Petro Poroshenko `` I just try to find out the time when he is more pragmatic than emotional . '' : The document is ` ` a statement of faith and unbreakable will '' The document shows ` ` how dramatically things can change in a short time , '' he says . State media : Vladimir Putin calls for ` ` substantial '' talks in Moscow , end to bloodshed .
NEW : Ukrainian President 's office : Cease - fire is in 72 hours . Ukraine 's Petro Poroshenko : The document is ` ` a statement of faith and unbreakable will '' The document shows ` ` how dramatically things can change in a short time , '' he says . State media : Vladimir Putin calls for ` ` substantial '' talks in Moscow , end to bloodshed .