KIEV: Ukraine's new Western-backed president said on Tuesday he may revoke his one-week unilateral ceasefire to allow government forces to retaliate for the downing by pro-Russian rebels of an army helicopter that killed nine servicemen.
"The head of state does not exclude that the ceasefire regime may be revoked ahead of schedule in view of its constant violation by rebels who are controlled from abroad," President Petro Poroshenko's office said in a statement that was clearly referring to Russia's alleged involvement in the 11-week insurgency.
Army officials said the Mi-8 helicopter was downed outside the rebel stronghold city of Slavyansk that has absorbed some of the heaviest fighting in Ukraine's Russified eastern rustbelt.
The Ukrainian army earlier reported fighting outside the city despite a temporary ceasefire being ordered by a top rebel commander on Monday evening.
Poroshenko said in his statement that gunmen had attacked government forces on 35 occasions since he ordered his troops to halt fire on Friday evening.
The statement added that Poroshenko met senior security officials on Tuesday evening and "issued an order to open fire in response (to rebel) attacks without any hesitation."
Poroshenko said that he hoped to address the violence at a meeting on Wednesday with Putin that would also be attended by German Chancellor Angela Merkel and French President Francois Hollande.
The Ukrainian president did not specify where the proposed meeting might be held.
Putin was in Vienna on Tuesday attending a meeting of the Organisation for Security and Cooperation in Europe.
The separatists' campaign has claimed the lives of 435 people and sparked the worst crisis in East-West relations since the Cold War.