Monday marks the anniversary of the foundation of the Ukrainian Insurgent Army (UPA), a group of nationalists who fought against Soviet troops in World War II alongside Nazi forces, Presstv Reported.
Nationalist forces customarily hold the "UPA March" on this date, with many of the former fighters in the conflict in eastern Ukraine among the demonstrators, as well as supporters of nationalist organization Svoboda.
October 14 has also been designated as Ukraine's armed forces day.
Meanwhile, President Volodymyr Zelensky is gearing up for a EU-supported summit with Russian leader Vladimir Putin, the first in years, in an effort to revive a stalled peace process for the region.
Protesters, however, said they saw any summit with Putin as a loss for Ukraine.
Zelensky took over in May from president Petro Poroshenko, pledging to end the conflict, but his efforts for new talks with Russia have been criticized.
The conflict in eastern Ukraine has become the worst East-West crisis since the end of the Cold War and claimed 13,000 lives.