For nearly three weeks, Chinese and Indian border troops have confronted each other close to a valley controlled by China that separates India from Bhutan - a close Indian ally - and gives China access to the so-called Chicken's Neck, a thin strip of land that connects India to its remote northeastern regions.

It has escalated tensions between the neighboring giants, who share a 3,500-kilometer (2,175-mile) frontier, large parts of which are disputed.

Beijing alleges Indian troops crossed into a region known in China as Donglang, called Doklam in India, early in June and obstructed work on a road on the Himalayan plateau.

Chinese officials say the Indian side's actions infringe upon an 1890 border agreement between Britain and China that previous Indian governments pledged to uphold.

Rising tensions

An Indian border soldier stands guard at the Nathu La border crossing with China

India, meanwhile, claims Chinese troops entered and tried to construct a road in Bhutanese territory. Landlocked Bhutan, a small Himalayan nation sandwiched between India and China, is hugely dependent on New Delhi and does not have diplomatic relations with Beijing.

Bhutan has said the construction of the road on its territory is "a direct violation" of agreements with China. "Bhutan hopes that the status quo in the Doklam area will be maintained as before June 16, 2017," its foreign ministry said last week in a statement quoted by AFP.

Although China and Bhutan have been negotiating the precise border for decades without serious incident, Bhutan this time sought help from India, which sent troops to the plateau to stop the Chinese workers.

Since then, videos have emerged showing Indian and Chinese soldiers blocking each other with their arms and physically jostling without coming to blows. China retaliated by closing a nearby mountain pass that Indian pilgrims use to reach Mount Kailash, a sacred Hindu and Buddhist site in Tibet.

The current confrontation seems to be the most serious in recent times and shows no signs of de-escalating. Both countries have upped the ante and deployed around 3,000 troops each in the tri-junction.

Read: Archrivals India, Pakistan enter China-led security bloc

Bellicose rhetoric

Xi and Modi meet in 2014 after agreeing to increase commercial ties

Chinese officials have also warned India that it should learn "historic lessons" from its humiliating defeat in the 1962 war that both countries fought over their border.

In response, Indian Defense Minister Arun Jaitley retorted that "India in 2017 is different from India in 1962," referring to its improved military strength.

"He (Jaitley) is right in saying that India in 2017 is different from 1962, just like China is also different," responded Chinese foreign ministry spokesperson Geng Shuang, adding China would take all necessary measures to safeguard its territorial sovereignty.

"At the moment there is no troop movement. Both sides must push for a political solution," Alka Acharya, a senior fellow of the New Delhi-based Institute of Chinese Studies, told DW.

The row has given a chance for the rabid press in both countries to stoke jingoistic feelings among their populations, aggravating the already deep-seated antipathy they share toward each other.

Indian media have issued shrill warnings about Chinese expansionism, while Chinese state media have ramped up their bellicose rhetoric, with the nationalist tabloid Global Times warning Wednesday that Beijing would make no concessions.

"The latest standoff in Sikkim and the discourse reflects China's desire to break the age-old bonhomie between Bhutan and India. India must brace for more Chinese rhetoric but observe patience," Srikanth Kondapalli, a professor in Chinese Studies at New Delhi's Jawaharlal Nehru University, told DW.

Read: India's Modi urges China to 'reconsider' approach to resolve disputes

China and India share a 3,500-kilometer (2,175-mile) frontier, large parts of which are disputed

Competing claims

The tensions have also spilled over into the G20 summit taking place on July 7-8 in Germany's Hamburg.

It's reported that a bilateral meeting between Chinese President Xi Jinping and Indian Prime Minister Narendra Modi had originally been on the cards, but then China said on July 6 that "the atmosphere is not right" for the two leaders to hold formal talks.

Nevertheless, Modi and Xi today shook hands and greeted each other at an informal meeting of BRICS, a grouping including Brazil, Russia, India, China and South Africa.

The two leaders also exchanged words of praise in their speeches and later discussed several issues.

At BRICS leaders' informal gathering, Modi and Xi "had a conversation on a range of issues," Foreign Ministry spokesperson Gopal Baglay tweeted.

China and India also have other competing territorial claims, which flare up now and then, resulting in minor border skirmishes.

In 2014, hundreds of Indian and Chinese troops faced off on the de facto border known as the Line of Actual Control that runs along the northwestern Indian region of Ladakh, overshadowing an India visit by President Xi.

China claims about 90,000 square kilometers (35,000 square miles) in the Indian province of Arunachal Pradesh, referred to informally by some Chinese as "Southern Tibet." India, on the other hand, claims sovereignty over 38,000 square kilometers (15,000 square miles) of the Aksai Chin plateau.

More than a dozen rounds of talks have failed to make substantial progress in the dispute, although there have been relatively few confrontations in recent years.