There is no trace of a former Pakistani military official who went missing in Nepal amid the row over the death sentence given to an alleged Indian spy. The Pakistani national, Muhammad Habib Zahir, is reported to have been sent on a clandestine mission to Nepal to carry out espionage activities.

India's former naval officer, Kulbhushan Jadhav, was recently sentenced to death by a military court in Pakistan, escalating tensions between the two nuclear-armed rivals. Against this backdrop, suspicion over Zahir's disappearance is likely to fall on New Delhi.

Zahir went missing on 6 April shortly after he was spotted at the Gautam Buddha Airport in Kathmandu. He was approached by an unknown individual at the airport, according to CCTV footage collected by authorities. His two mobile connections, both Nepali and Pakistani numbers, remain unreachable.

Nepali authorities are clueless about Zahir's sudden disappearance. "The police are trying to ascertain the identity of the person who received him," senior police official Tipak Thapa told the BBC Urdu. Zahir retired from army services in 2014.

Photographs of Zahir have been circulated among local drivers and officials but none of them have shed any light on his possible whereabouts.

Nepal formally informed Pakistan about the incident prompting Islamabad's interior ministry to jump into action.

"We are not aware as to why Col Zahir went to Lumbini and what his purpose of visit to Nepal was. There was no room booked in his name in any hotel there," Nepali interior ministry spokesperson, Krishna Panthi, said.

Indian intelligence, cited by media outlets, has rubbished any allegations linking Zahir's disappearance with the death sentence of Jadhav. Tensions between the countries, which have fought three wars since their independence, are high and the death sentence would only aggravate the already surcharged atmosphere.