DONETSK, Ukraine — Ukraine's president vowed vengeance in blood after 19 troops were killed in an insurgent rocket attack Friday, and residents of the rebel-held city of Donetsk began fleeing in large numbers for fear of a government siege.
The barrage of rocket fire before sunrise at a base near the Russian border was a devastating setback for government forces, who had seemingly gained the upper hand last weekend when they pushed the pro-Russian fighters out of their stronghold city of Slovyansk. In addition to those killed, 93 soldiers were wounded, the Defense Ministry said.
"For every life of our soldiers, the militants will pay with tens and hundreds of their own," Ukrainian President Petro Poroshenko warned.
Ukrainian government troops have been fighting for more than three months against separatists in eastern Ukraine, and in the last two weeks, they have cut the territory held by the rebels in half.
Driven from Slovyansk, the rebels have regrouped in Donetsk, an industrial city of 1 million, and Ukraine has said it will cordon off the area.
In anticipation of a siege, leaders of the self-styled Donetsk People's Republic announced they will evacuate entire neighborhoods. Tens of thousands of residents have rushed to pack up and leave for fear of getting caught in the cross fire.