Kulbhushan Sudhir Jadhav was arrested last year in the Balochistan province of Pakistan and convicted on charges of spying for Indian intelligence services.
India on Monday appealed to the United Nation's top court to order Pakistan to suspend its planned execution of an Indian national convicted of spying in a case that has escalated tensions between the two countries.
Kulbhushan Sudhir Jadhav, an Indian former naval officer was arrested in March 2016, in the Pakistani province of Balochistan, where a separatist insurgency has raged for years.
After his arrest, Pakistani officials said that he had confessed to spying for Indian intelligence services. He was sentenced to death by a Pakistani military court last month.
However, India has denied he was a spy, and last week lodged a protest at the at the UN court in the Hague, formally known as the International Court of Justice (ICJ), accusing Pakistan of violating the Vienna Convention on Consular Relations by denying the condemned man access to legal and other assistance from India.
India and Pakistan routinely accuse one another of sending spies into their countries, and it is not uncommon for either nation to expel diplomats accused of espionage, particularly at times of high tension. But death sentences have rarely been issued in recent years.
Jadhav's case comes as relations have plummeted since a deadly attack on an Indian army base in the disputed region of Kashmir in September, which New Delhi blamed on a Pakistan-based militant group.
There have since been repeated outbreaks of cross-border firing, with both sides reporting deaths and injuries.