Three wars later, the decades-old rivalry between nuclear-armed India and Pakistan continues.

In recent news from the northern Indian state of Punjab, a pigeon has been detained by police in the village of Manwal, near the India-Pakistan border, on suspicion of being used for spying.

The stool pigeon landed on the house of a local barber, Ramesh Chandra, allegedly after flying in from Pakistan across the border.

After the barber's son found a note in Urdu under the pigeon's feathers bearing the name of a Pakistan district, he took the bird to the nearest police station.

"Tehsil Shakargarh, district Narowal" read the writing on the pigeon that was accompanied with a string of numbers, reported The Guardian.

Indian police said on 29 May that the pigeon was being treated as a "suspected spy" and subjected to an X-ray to determine if it was fitted with a spying device.

"We sent the bird to a polyclinic where X-ray scans were done to see if there is any spy camera, transmitter or hidden chip," Rakesh Kaushal, a senior police official told AFP News.

"Till now there is no evidence to suggest it is a spy bird but so long as we are not able to decipher what is written in Urdu, we cannot be absolutely sure."

So far, investigators have found no "camera, no chips, no SIM cards," however intelligence services have been alerted.

"This is a rare instance of a bird from Pakistan being spotted here. We have caught a few spies here," said Kaushal.

"The area is sensitive, given its proximity to Jammu, where infiltration is quite common."

Till the investigations continue, the pigeon will be held as a jailbird.

In 2013, Indian police found a dead falcon on the Pakistani border with an antennae and camera suspected to have been used for spying.

Masquerading monkeys and secret squirrels

Other animals have been "arrested" on suspicion of spying over the years.

During the Napoleonic Wars, a French ship was wrecked off the coast of Hartlepool. The only survivor was a monkey, allegedly wearing a French uniform to provide amusement for the crew, and, some locals decided to hold an impromptu trial on the beach. As the monkey was unable to answer their questions and because they had seen neither a monkey nor a Frenchman before, they concluded that the monkey was in fact a French spy. Being found guilty, the animal was duly sentenced to death and hanged on the beach.

In 2011, Saudi authorities arrested a high-flying vulture on suspicion that it was flying missions for Israel's Mossad agency.

And a spate of shark attacks near the Red Sea resort of Sharm el-Sheikh in 2010 was blamed by one TV station on GPS-controlled predators planted by Israel in order to harm the Egyptian tourism industry.

Iran, too, has also felt threatened by animal agents. In 2007 the Iranian army arrested a team of 14 "spy squirrels" found near a nuclear enrichment plant. Officials said they succeeded in apprehending the suspects "before they were able to take any action".