New Delhi, May 10: India has tightened its regulations to issue medical visas to Pakistani citizens, the move coming amid heightened tensions over the conviction and sentencing to death of former Indian navy officer Kulbhushan Jadhav by a Pakistan military court.

Pakistani nationals keen to travel to India for treatment will now need to submit letters of endorsement from their country's de-facto foreign minister Sartaj Aziz along with other documents and their visa applications, the foreign ministry here said.

The decision may impact hundreds of Pakistani citizens who each year apply for, and obtain, medical visas from the Indian high commission in Islamabad to visit India for treatment.

The move is the second by India over the past eight days involving humanitarian relations that the two nations have long tried to shield from their larger bilateral tensions. India last week sent back 50 Pakistani schoolchildren who were visiting at the invitation of a non-profit group and had arrived on the day Pakistani soldiers allegedly beheaded two Indian soldiers.

"We want to have some verification from the Pakistani government," foreign ministry spokesperson Gopal Baglay said. "That is all we are seeking. There is no ban on medical visas for Pakistani nationals."

The change, Baglay said, was a consequence of a flood of medical visa applications addressed directly to foreign minister Sushma Swaraj, which the foreign office was receiving from Pakistan. It was difficult, officials said, to sieve through those applications and advise the high commission without vetting from the Pakistan foreign ministry.

But the new rules are unique to Pakistani nationals - citizens from other countries applying for Indian medical visas are not required to submit endorsements from their foreign ministers.

Over 150,000 foreigners visit India each year on medical visas, mostly from developing nations, attracted by the combination of quality medical care and relatively affordable costs that many Indian hospitals offer.

This number has doubled since 2014, pointing to the explosion within the Indian medical tourism market which was valued at $3 billion in 2015 and is expected to touch $8 billion by 2020.