STORY: A Bulgarian street artist, Stanislav Belovski, told Reuters he normally displayed his works in galleries. "When I go in the streets, it is because I want to share a message with people who would hardly listen to artists."
His artwork, showing a mother holding a gun and her child's hands, can now be seen in the streets of Sofia.
Some artists created images with slogans like "No to war", "Stop War", "To Ukraine with Love" and "Hope".
Russia's invasion, which Moscow calls a "special military operation", has killed thousands of people and displaced nearly 10 million. It has also left Russia in the grip of tough Western sanctions and has raised fears of a wider confrontation between Russia and the United States - by far the world's biggest nuclear powers.