Do an image search for Victory Salute. About 1/4 of the images are people holding a single hand with a fist up.
Did you get a translation of what he said? It was probably something along the lines of "We did it, we kicked them out".
The Lore of the Victory Salute
Preliminary note : I'm very grateful to all the sources of these pictures. Some of them are great photos taken by hard working people and we...cozybeehive.blogspot.com
The guy parading with the Ukranian flag didn't say anything that I could discern. It sounds like you're looking at the photo of Rogozin with his fist up. He has definitely given the Nazi salute at white supremacist rallies in the past.