On Tuesday in Parliament, the opposition Congress said that Prime Minister Narendra Modi must step in to secure the release of former Indian Navy officer Kulbhushan Jadhav - sentenced to death in Pakistan.
Congress's Mallikarjun Kharge questioned, "Pakistan has sentenced Kulbhushan Jadav on lies and false allegations of spying. Why is the government silent?"
"If Pakistan hangs Kulbhushan Jadhav, then it is murder. The government will be seen as weak if it cannot free him," Mr Kharge said.
Hyderabad lawmaker Asaduddin Owaisi said, "The government has influence, please use it. Will the government make every effort to save him? It is our joint responsibility to save him."
Kulbhushan Jadhav was arrested in March last year by Pakistan for alleged 'spying'. On Monday, he was sentenced to death by a Pakistani military court.
"If this sentence against an Indian citizen, awarded without observing basic norms of law and justice, is carried out, the government and people of India will regard it as a case of premeditated murder," the Foreign Ministry said.
India has also retaliated by deciding it will not release 12 Pakistani prisoners who were cleared to return home tomorrow.