India on April 11 warned Pakistan of "consequences" for bilateral relations if Islamabad executes a retired Indian naval officer convicted of spying.
A Pakistani military court handed the death sentence to Kulbhushan Jadhav on April 10, convicting him of spying and fomenting unrest in the province of Balochistan.
Indian Foreign Minister Sushma Swaraj condemned the "farcical" trial, and told agitated Indian lawmakers that there was no evidence against Jadhav.
"I would caution the Pakistan government to consider the consequences for our bilateral relationship if they proceed on this matter," she said.
Home Minister Rajnath Singh claimed Jadhav, who was engaged in a business in Iran, was abducted by Pakistani security forces a year ago and branded a spy.
Pakistan's army released a video of Jadhav confessing to spending years sowing unrest in Pakistan.
Swaraj said the Indian government "will go out of the way to save" him, calling any execution "an act of premeditated murder."
She said Islamabad has repeatedly blocked consular access to Jadhav.
Meanwhile, the Indian government has also stalled the release of 12 Pakistani prisoners who were due to be repatriated on April 12, broadcaster NDTV reported.