Following the loss of at least 19 soldiers in a rocket attack Friday morning by the pro-Russian militia, Ukrainian officials have claimed to have killed large numbers of rebel combatants, although there has been no independent verification. Late on Friday, Defense Ministry spokesman Vladislav Seleznev said on his Facebook account that 1,000 rebels had been killed in two separate airstrikes.
Poroshenko vowed last week to respond with firmness to attacks by the pro-Russian insurgency.
"For every life of our soldiers, the militants will pay with tens and hundreds of their own," Poroshenko warned Friday. "Not one terrorist will evade responsibility. Everybody will get what is coming to them."
Peter Leonard in Kiev, Ukraine and Balint Szlanko in Donetsk, Ukraine contributed reporting.
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