Pro-Russian separatists in eastern Ukraine have accused President Petro Poroshenko of scrapping a deal aimed at halting months of war, reports GHN based on BBC.
They were responding to Mr Poroshenko's call to cancel partial autonomy granted to two eastern regions as part of a ceasefire agreement.
The Ukrainian president and Western countries say a rebel vote held in the east on Sunday violated the Minsk deal.
He has ordered reinforcements to key cities in case of a rebel offensive.
More than 4,000 people have died in eastern Ukraine since the conflict began in April and the European OSCE monitoring mission has warned that the "blood-letting" is still going on with numerous incidents of shelling.
A civilian was reported killed and several others wounded in mortar attacks on Donetsk on Wednesday. Clashes were also heard around Donetsk airport, AFP news agency said, where government forces have been holding out against rebel attack.
Although Mr Poroshenko insisted he had not given up on the peace plan, he said Ukraine had to "repel possible attacks" and not allow the "spread of this cancerous tumour".
Russia has recognised Sunday's vote which led to separatist leader Alexander Zakharchenko, 38, being sworn in as president of the self-declared Donetsk People's Republic.