A First Information Report under Section 309 (attempt to commit suicide) of the Indian Penal Code was registered against them yesterday.
Jailer P K Palat, the complainant, has said in the FIR that Shakil Ahmed Abdul Salim and 21 others have been on indefinite fast since October 15.
They are among 47 men lodged in Sabarmati jail for alleged involvement in the serial blasts of July 2008 here.
"After the tunnel was discovered two years ago, they have been lodged in the high security barracks.... Now, they want the jail authorities to let them roam free outside their barrack. We have registered a complaint and started a probe," said inspector K D Champavat.
Twenty-one blasts rocked Ahmedabad city on July 26, 2008, claiming 56 lives.