One leaflet attached to a lamp post near the Atyrau recreation center read: "Chechen Republic. Free Jahar [Dzhokhar]. In support of the Tsarnaev brothers," the Ak Zhaik newspaper of Atyrau reported Wednesday.
Another leaflet on a nearby pole read: "Dzhokhar Tsarnaev is innocent," and included a photo of the 19-year-old.
Kazakhstan borders Kyrgyzstan, where the Tsarnaev family lived before moving to the United States about a decade ago. The family also has Chechen roots and once lived in Dagestan in Russia's North Caucasus region.
Tsarnaev is accused of carrying out the April 15 bombing of the Boston Marathon with his brother, Tamerlan, 26, who was killed during a police pursuit. Two bombs killed three people and injured more than 260 others near the marathon finish line, and a fourth person -- an Massachusetts Institute of Technology public safety officer -- was killed in a later gunfight with the brothers.