Kiev - Ukraine remains committed to a peace process with pro-Russian separatists, but is rearming and prepared for war should they attempt to launch a new offensive, President Petro Poroshenko said on Tuesday.
Speaking at the start of a crisis meeting of security chiefs in the capital Kiev, Poroshenko said that he had not given up on a deal brokered in September to end the seven-month conflict, in which more than 4 000 people have died.
"Ukraine remains a firm supporter of the peace plan," Poroshenko said. However, "other participants" of the Russian-supported truce accord are not meeting their obligations, he said, referring to Moscow and the rebels.
Poroshenko warned that Ukraine's military was ready for any separatist attempt to expand the territory they control - as they have repeatedly threatened to do.
"We are obliged as the Ukrainian state not to allow the spread of this cancerous tumour, to ensure the blockade of this territory," he told his National Security and Defence Council.
The meeting was called after separatists staged leadership elections that were backed by Russia, but condemned by Ukraine, the United States, EU powers, and the head of the United Nations.
Poroshenko said the "pseudo" elections on Sunday had "torpedoed" a key provision of the September peace deal in which rebels would be given wide autonomy, while preserving Ukraine's integrity.
The September accord - signed by Ukraine, the rebels, Russia and the European security body OSCE in Minsk - was meant to pave the way for a ceasefire and ultimately a political settlement.
But Poroshenko said he was now considering scrapping the autonomy offer, a measure at the heart of the whole peace plan.
Constant ceasefire violations have already undermined the truce, with fighting breaking out again Tuesday near the rebel-held city of Donetsk.
Inaugurations and fighting
In the two rebel enclaves in the east, the Kremlin-backed leaders added to the trappings of statehood with post-election inaugurations.
At a swearing-in ceremony in Donetsk's main theatre, separatist chief Alexander Zakharchenko - a former electrician who was already undisputed rebel commander - took an oath on a Bible "to serve the people."
In neighbouring Lugansk, Igor Plotnitsky - a burly ex-Soviet army officer - was also confirmed as rebel supremo there, Russian media reported.
Zakharchenko, 38, said that he was ready to meet with Poroshenko for discussions but insisted Kiev negotiate with the rebels as equals.
"Ukraine has to understand that the [Donetsk People's Republic] is already another state," he told Russian radio station Echo of Moscow.
Meanwhile, artillery bombardments started up again outside Donetsk.
"Very heavy firing started from 06:30 this morning," said local resident Tatyana. "It's hellish."
Analysts in Ukraine have warned that a surge in the fighting could follow the rebel elections. Zakharchenko has repeatedly stated that his forces intend to capture more territory, specifically the Black Sea port city of Mariupol.
Poroshenko said Ukraine was capable of withstanding an offensive.
Ukraine will be "prepared for decisive measures in the case of a negative scenario," he said. "Today, several new units and groupings have been formed, which will already allow us to stop any possible attack" further toward the west, he said.
Ukraine's small army has been badly mauled during the more than half-year of battles with rebels who Western governments say are supplied and supported by regular Russian troops.
However, Poroshenko said "the supply of our armed forces with the very latest technology - offensive, reconnaissance, guided systems - is continuing quite effectively."
Angry international reaction
The new EU foreign policy chief, Federica Mogherini, said the rebel elections threatened to scuttle any chance of a peaceful solution to the bloody crisis.
"The main risk I see now is that we close this window of opportunity for internal dialogue and for dialogue with Russia" on implementing a peace plan all sides agreed in September, Mogherini said at a press conference with Nato chief Jens Stoltenberg.
Although Moscow has not recognised the rebel statelets' independence, its endorsement of the elections' validity added fuel to an already heated row with the West.
The United States followed Europe in hammering Sunday's rebel polls, which showed Ukraine's inability to control the eastern region and were conducted without recognised election observers.
"These sham elections contravened Ukraine's constitution... and the most basic electoral norms," said the White House, while the State Department warned Moscow that it risked further isolation by recognising the polls.
United Nations Secretary General Ban Ki-moon on Tuesday also slammed the vote as "unfortunate and counter-productive" and called on all sides to return to the peace plan.
Russia's announcement that it "respected" the outcome of the rebel polls could lead to tougher EU and US economic sanctions - or at least new determination to keep the current measures in place.
French President Francois Hollande said sanctions against Russia are "essential... but they should not be the sole response.
"The objective is to convince Moscow and the separatists to renounce escalation and to return to a dialogue."
The separatist uprisings in the pro-Russian corner of Ukraine started shortly after Russia's troops invaded and annexed Crimea, a southern Ukrainian region, in March.
