A helicopter carrying three Indian Air Force officers on a flood rescue mission has gone missing near the country's border with China, a defence official has said.

The aircraft which took off in Assam is said to have lost contact with colleagues on the ground after hitting turbulent weather in Arunachal Pradesh.

India's junior home minister Kiren Rijiju tweeted that efforts were on to locate the chopper, which was carrying relief material for flood-affected residents in the northeast of the country.

Advanced Light Helicopter (ALH) of the Indian Air Force's Sarang aerobatics team perform during the Air Force Day parade at Air Force Station Hindon in Ghaziabad town on the outskirts of New Delhi in October 2016 - one chopper is now missing

The chopper lost contact over mountainous Arunachal Pradesh on Tuesday in bad weather - the state, as well as some other neighbouring states, have been reeling under heavy monsoon rains that have triggered landslides and floods (picture for representation only)

'The ALH (Advanced Light Helicopter) had taken off from Tezpur airbase in Assam state around 4pm (10:30 GMT),' the official said, declining to be named.

Arunachal Pradesh as well as some other neighbouring states have been reeling under heavy monsoon rains that have triggered landslides and floods.

China and India have a border dispute in the mountainous northeast and regularly accuse each other of making illegal troop encroachments.

An Indian security personal stands guard in the Tewang District near the Chinese border in India's north-eastern state of Arunachal Pradesh

Demonstrators shout slogans as they protest against China's claim of six districts of Arunachal Pradesh state in New Delhi in April

Their mistrust stems from a brief war in 1962 over Arunachal Pradesh which has a large ethnic Tibetan population.

The standoff has intensified in recent days with the two sides trading stern diplomatic warnings over a remote scrap of territory where the frontiers of China, India and Bhutan meet.

China last week accused Indian border guards of crossing from Sikkim state into Tibetan territory and ordered the 'trespassers' to withdraw in a formal protest.

Chinese soldier (L) and an Indian soldier stand guard at the Chinese side of the ancient Nathu La border crossing, where tensions have flared between both sides in recent weeks

China has also deployed a Yuan class submarine in the Indian Ocean, in what is widely seen as an aggressive move

In apparent retaliation, China has blocked Indian pilgrims from crossing the border in the mountainous area 'out of security concerns', the Chinese foreign ministry said.

But China on Monday said it would continue to allow Indian pilgrims to Kailash Mansarovar through the Lipulekh pass in Uttarakhand.

Meanwhile, a Chinese submarine venturing into Indian Ocean waters has raised eyebrows in India, which widely sees the presence of the vessel as an aggressive move.

It is the seventh submarine belonging to the Chinese People's Liberation Army to be deployed in the area, officials said.

'Indo-China armed conflict is possible'

While for the first time this week China relented from its war of words with India, state media outlets in Beijing instead begun drawing parallels to 1962 and speaking of 'teaching India a lesson'.

An article published on the PLA website by strategic expert Wang Dehua warned that 'those in India who still uphold 'confrontation' in this event should be fully aware of the fact that if a solution isn't reached through diplomatic or military communication or the issue isn't handled properly, another armed conflict between China and India is not completely out of question.'

Wang, who is the head of the Institute of South and Central Asia at the Shanghai Institutes for International Studies, said that 'some Indians dare to provoke China and even claim that it's not 1962 anymore probably because they don't think China has military advantages at the border sector where the event took place.

Armed expulsion of trespassing Indian troops would be China’s last resort, says Wang Dehua

'They mistakenly think that India can avenge itself by using the favourable terrain and its advantageous mountain division and air force on the border. But India would do better to not forget the historical lesson,' he said.

Prior to the June 16 stand-off and China's statements last week, Chinese media rarely have referred to 1962.

This week appears to be an exception, with the PLA spokesperson on Thursday reminding India of 'historical lessons' and numerous references to 1962 in China's state media.