At least seven undertrial prisoners were injured in a clash between two criminal groups in Dhanbad jail on Sunday, police said.
Prisoners Sanjay Mahto and Diwakar Mahto, who were collecting weekly extortion of Rs 500 to Rs 1,000 from each prisoner, thrashed three other prisoners which led to the clash.
"The three prisoners were thrashed as they opposed the demands of Sanjay and Diwakar. Seven prisoners were injured in the clash that followed," a police officer said.
He said five injured have been admitted in a jail hospital while the rest were referred to Patliputra Medical College and Hospital (PMCH), Dhanbad.