New Delhi - India has increased the number of troops along its northeastern border with China, reports said on Friday, amid a tense stand-off between Delhi and Beijing over a strategically key Himalayan plateau.The "caution level" among the troops has also been raised, the Press Trust of India news agency said, quoting an unnamed government official."The troop level along the border with China in the Sikkim and Arunachal sectors has been increased," the official said without giving further details.The official however said there was no deployment of extra troops at the tri-junction between India, China and Bhutan, where around 350 Indian army personnel have been locked in a face-off with Chinese troops for nearly seven weeks.The border trouble began in June when Chinese soldiers started to extend a road through the Doklam territory - known as "Donglang" in Chinese. The area is disputed between China and Bhutan.India, a close ally of Bhutan, then deployed troops to stop the construction project, prompting Beijing to accuse India of trespassing on Chinese soil.China insists that India must withdraw its troops before any proper negotiation takes place. India said both sides should withdraw their forces. The plateau is strategically significant as it gives China access to the so-called "chicken neck" - a thin strip of land connecting India's northeastern states with the rest of the country.Mistrust between the giant neighbours is hundreds of years old with the pair having fought a brief war in 1962 in India's border state of Arunachal Pradesh.