Awarding of death sentence to Kulbhushan Jadhav in Pakistan shows how the country's military court system rides "roughshod" over international standards, Amnesty International on Monday said.
In a strongly worded statement, the rights body said military courts are an inherently "abusive system" that are best left to deal with issues of military discipline, not any other crime.
"The death sentence given to Kulbushan Jadhav shows yet again how Pakistan's military court system rides roughshod over international standards. Stripping defendants of their rights and operating in notorious secrecy, military courts do not dispense justice...," said Biraj Patnaik, South Asia Director of Amnesty International.
Amnesty opposes the death penalty at all times and in all circumstances, regardless of who is accused, the crime, guilt or innocence, or the method of execution, he added.
The statement came in reaction to the Pakistan army chief approving execution of Jadhav for his "involvement in espionage and sabotage activities" in that country.
Pakistan security officials had "arrested" Jadhav on March 3 last year in Balochistan after he reportedly entered from Iran.
Pakistan has alleged that Jadhav was a serving officer in the Indian Navy and deputed to the Research and Analysis Wing (R&AW).
India has acknowledged Jadhav as a retired Indian Navy officer, but denied the allegation that he was in any way connected to the government.
India has said Jadhavs execution would be treated as a "premeditated murder".