Ukrainian President Petro Poroshenko is warning he may end the weeklong ceasefire ahead of time, after pro-Moscow separatists shot down a Ukrainian military helicopter.  Nine Ukrainian service members died in the attack, which occurred just a day after rebel leaders claimed they would honor the ceasefire through Friday.

The Mi-8 helicopter had just taken off from outside the city of Sloviansk when separatists launched a shoulder-fired missile at it.  Separatists have shot at Ukrainian forces at leas 35 times since Poroshenko announced the ceasefire.  He has now ordered his troops to fire back “without hesitation” if it happens again.

“The president doesn’t exclude that the cease-fire could be lifted ahead of time, taking into account its constant violation by the rebels controlled from abroad,” read the statement from Poroshenko’s office.  Rebel leaders say the ceasefire appears to have collapsed.

Meanwhile, Russian President Vladimir Putin is urging Poroshenko to do the opposite, to extend the ceasefire and continue talks with the rebels.  Putin also moved to rescind a parliamentary resolution authorizing him to use the Russian military in Ukraine.