The trouble between Dalits and the Bharwad (Shepherd) community members started at the Tarnetar fair held near Thangadh in Surendranagar district which concluded yesterday, police said.
The members of the two communities reportedly clashed over some issue after the fair.
The police first resorted to lathicharge and then fired tear gas shells, they said. When the violence continued, police fired in the air in which a Dalit boy was killed while two others were seriously injured.
They succumbed today, police said.
"To quell the mob, police first resorted to lathicharge, then fired tear gas shells, but as violence continued and stone throwing started, we had to fire in air," a police official said.
Meanwhile, clashes between the two groups flared up again this afternoon, police said, adding, security has been stepped up in the area.