Demonstrators also denounced Ukrainian President Volodymyr Zelenskyy's efforts to secure a lasting cease-fire along the tense line of contact in the conflict with Russia-backed separatists.
The conflict in Ukraine's eastern industrial heartland called the Donbas erupted in 2014, weeks after Moscow annexed the Crimean Peninsula following the ouster of the country's Russia-leaning president. The fighting between Ukrainian forces and Russia-backed rebels has killed more than 14,000.
A 2015 peace deal signed in Minsk has helped end large-scale fighting, but frequent skirmishes have continued and efforts to achieve a political settlement have failed.
They also assailed Zelenskyy's efforts to end skirmishes across the line of contact as a betrayal of national interests.
Earlier this year, a spike in clashes in the conflict area and a buildup of Russian troops across the border fueled fears of a renewal of full-scale hostilities.
Zelenskyy on Thursday traveled to the conflict area. Speaking to military cadets, he emphasized the importance of reaching a peaceful settlement.