The antiwar demonstration was organized by liberal parties, but there appears to be some participation by Russian nationalists.
A good long-read about the split in the Russian far-right over Ukraine here.
Our Moscow correspondent, Tom Balmforth, who is on the scene, speaks to Daria Nikolaeva, a 55-year old Russian teacher.
"I'm not only against us sending our troops to Ukraine," she says. "I'm against us interfering whatsoever in the matters of other sovereign states. Crimea set a precedent."
"I demand Russian troops leave Ukraine! -- Russian citizen"
Hundreds of demonstrators marched in Dnipropetrovsk on September 21 to protest against the separatist conflict in the country's east. Dnipropetrovsk, Ukraine's third-largest city, is within close reach of the regions controlled by pro-Russian separatists. The demonstration took place as other major peace protests were under way in Moscow, St. Petersburg, and elsewhere in Russia and Ukraine. (RFE/RL's Ukrainian Service)
Moscow police say 3,000 some 5,000 have turned out; protest organizers say up to 40,000. An AP journalist on the scene estimates "at least 10,000."
According to our reporters on the scene, some counter-protesters have also thrown eggs at antiwar demonstrators, but the march has generally proceeded peacefully. Unlike past opposition marches, which often include an array of different interests, this appears to be squarely focused on the conflict in Ukraine and there have been few chants besides "No war in Ukraine."