The apex body of Protestant churches on Saturday flayed the life sentence handed down to rights activist Binayak Sen by the Raipur sessions court.
The National Council of Churches in India (NCCI) condemned the "unjust attitude" of the Chhattisgarh government and described Sen's conviction as a "politically motivated" decision.
"NCCI strongly condemns such unlawful activities of states in shutting up whistle blowers' voices against structural injustices on communities by misusing the state and legislative machineries," the general secretary, Rev. Dr. Roger Gaikwad, said in a statement.
He criticised the verdict as a "vindictive action" to weaken civil society movements that "fight for dignity of life and livelihood."
Sen was sentenced to life imprisonment after being convicted of sedition for allegedly helping Maoist rebels in their fight against the state.
The NCCI demanded that the "state and federal authorities immediately drop these politically motivated charges against Sen and release him immediately."
The prison term awarded to Sen has apparently sparked outrage among rights activists in India and across the world.
Amnesty International, which called Sen a prisoner of 'conscience', slammed the verdict saying it "violated international fair trial standards."
"Life in prison is an unusually harsh sentence for anyone, much less for an internationally recognized human rights defender who has never been charged with any act of violence," Sam Zarifi, Amnesty's Asia-Pacific director, said in a statement.
"Instead of persecuting Dr. Sen, the authorities in Chhattisgarh should be acting to protect the people of the region from the abuses committed by Maoists, as well as state security forces and militias."
An alumnus of the Vellore Christian Medical College of Tamil Nadu, Sen worked for over 30 years to bring healthcare to Chhattisgarh's tribal population for which he won the 2008 Jonathan Mann Award for Global Health and Human Rights.
As vice president of the People's Union for Civil Liberties, Sen also campaigned against unlawful killings of adivasis and violation of human rights in tribal areas.