ISLAMABAD -- The International Court of Justice in the Hague is set to hand down its verdict on Wednesday in an unusually contentious case involving India and Pakistan over Islamabad's allegations of spying by an Indian.

Kulbhushan Jadhav, who Pakistani officials alleged is an Indian naval officer-turned-spy, was arrested in 2016 in Pakistan over accusations that he organized terrorist attacks in the country's southwestern Balochistan province. He was subsequently sentenced to death by a Pakistani military court.

India has refuted the charges on grounds that Jadhav was framed by Pakistan's intelligence services. Delhi has approached the international court for consular access to Jadhav. Western diplomats told the Nikkei Asian Review that Delhi is seeking to reverse the verdict slapped on Jadhav in Pakistan.

"This man has plenty of blood on his hands and he must face justice," said a senior Pakistani government official who spoke to Nikkei on condition of anonymity.

"Our [Pakistan's] investigation has linked Jadhav to supplying ammunition and explosives to insurgents in Balochistan, to attack locations in that region. There was overwhelming evidence that led to his death sentence," he added.

Western diplomats warned that if Pakistan executes Jadhav, relations between the two neighbors will sink to a new low. "If Pakistan hangs Kulbhushan Jadhav, India will see that as an offensive act. And the public across India will demand revenge," said one senior western diplomat who spoke to Nikkei on condition of anonymity.

Tensions between the two nuclear-armed countries rapidly heated up in February after terrorists attacked the part of Kashmir controlled by India. Delhi was quick to point the finger at Pakistan-backed Islamic militants. Pakistan denied the charge.

Analysts said the Jadhav case is a powerful reminder of how quickly things can spiral out of control between the two.

"The Kulbhushan Jadhav case shows us the complicated nature of Indo-Pakistan relations. Whichever way the [ICJ] verdict goes, one side will see this as a victory while the other will not," said retired Major General Mahmud Durrani, a former national security adviser to the prime minister's office.

Other political experts also said it would not be in Pakistan's interest to execute Jadhav. "I personally don't believe Pakistan should put Kulbhushan Jadhav to death," said Aziz Khan, a former Pakistani ambassador to India. "Maybe in future we can use Jadhav as a pawn in a prisoner exchange." India and Pakistan have a history of capturing citizens from the other side on espionage charges.

But ahead of the ICJ verdict, Pakistani officials claimed that the accusations leveled at Jadhav is based on "solid" evidence. "There is very little doubt in the evidence that we have collected on Kulbhushan Jadhav. He is a man who deserves to be punished and Pakistan is in no mood to let him go free," said the senior Pakistani government official.