Venus, as seen by the Magellan spacecraft, 1991

Mysterious 'aircraft' were sighted 329 times hovering over a lake on the border between the two countries

Indian army personnel operating on the disputed Himalayan border with China reportedly spent six months observing suspected Chinese spy drones before finding out the objects were planets.

After 329 separate sightings and 155 violations of the Line of Actual Control (the Himalayan border between the two nations) officials recruited a team of astronomers to find out exactly what the mysterious intruders were.

After close observation the astronomers reported that the 'aircraft' spotted in the sky were in fact Venus and Jupiter.

“Our task was to determine whether these unidentified objects were celestial or terrestrial,” said Tushar Prabhu, a senior astronomer who spoke to Calcutta-based paper, The Telegraph.

Prabhu's team were informed that one object was visible from a vantage point nearly 5,000 metres above sea level, appearing in the horizon from about 6pm until 5am the next day. A second appeared at 4am but had disappeared without fail by 11 the same morning.

Despite army personnel reporting that the objects appeared as the brightest lights in the sky and that they always seemed to move in relation to the stars, it was not until astronomers requested that the army record a log of horizontal and vertical elevations for the figures that they were identified as planets. Their apparent motion was due to the rotation of the Earth.

Although the mistake seems rudimentary, the area where the incident occured is a notorious hotspot for disputes between the two countries; border violations in the region were used as a pretext for the 1962 India-China War.

As the use of drones for surveillance rises in popularity the number of trangression reported in the region has escalted. With such a history it's no surprise that tensions are high.