NEW DELHI (NYTIMES) - High in the Himalayas, an enormous fistfight erupted in early May between the soldiers of China and India.
Brawls at 4,260m along their inhospitable and disputed frontier are not terribly unusual, but what happened next was.
A few days later, Chinese troops confronted Indian soldiers again, this time at several other remote border points in the Himalayas, some more than 1,600km apart.
Since then both armies have rushed in thousands of reinforcements. Indian analysts say that China has beefed up its forces with dump trucks, excavators, troop carriers, artillery and armoured vehicles and that China is now occupying Indian territory.
No shots have been fired, as the de facto border code dictates, but the soldiers have fought fiercely with rocks, wooden clubs and their hands in a handful of clashes.
In one melee at the glacial lake Pangong Tso, several Indian troops were hurt badly enough that they had to be evacuated by helicopter, and Indian analysts said Chinese troops were injured as well.
Nobody thinks China and India are about to go to war. But the escalating build-up has turned into their most serious confrontation since 2017 and may be a sign of more trouble to come as the world's two most populous countries increasingly bump up against each other in one of the bleakest and most remote borderlands on earth.
US President Donald Trump, unsolicited, stepped in on Wednesday (May 27), offering on Twitter to mediate what he called "a raging border dispute".
For India, the Chinese incursions and manoeuvres at multiple points along the more than 3,370km border have raised suspicions of a concerted campaign to exert pressure on the government of Prime Minister Narendra Modi.
With the world consumed by the coronavirus pandemic, China has acted forcefully to defend its territorial claims, including in the Himalayas.
In recent weeks, the Chinese have sunk a Vietnamese fishing boat in the South China Sea swarmed a Malaysian offshore oil rig menaced Taiwan and severely tightened their grip on the semi-autonomous region of Hong Kong.
The confrontation with India "fits a broader pattern of Chinese assertiveness", said Dr Tanvi Madan, director of the India Project at the Brookings Institution in Washington, noting that it was the fourth flare-up since China's authoritarian leader, Mr Xi Jinping, rose to power at the end of 2012.
India's government has disclosed few details about what had actually happened, saying in a statement only that it was the "Chinese side that has recently undertaken activity hindering India's normal patrolling patterns".
Mr Modi, who is usually outspoken in defence of his country's interests, appears intent on avoiding an escalation, analysts said.
"The military skirmishes and standoffs with India seem to reflect Beijing's calculation that India's still-increasing Covid-19 infections, coupled with its economic downturn, place it in no position to wage a border conflict," said professor of strategic studies Brahma Chellaney of the New Delhi-based Centre for Policy Research.
All this, he added, could also be "Beijing's way of sending a political message" to India not to get too close to the United States and to back off its criticism of the way China has handled the coronavirus.
Even before the scuffling, India was feeling increasingly hemmed in by China's expanding economic and geopolitical influence in South Asia.
To the west, the Chinese are working with Pakistan, India's archenemy, and recently agreed to help construct an enormous dam on the border of Pakistan-administered Kashmir, an area India claims.
To the east, China's new friend, Nepal, just produced a map that challenges where the Indian border lies; India has blamed China for stirring up the trouble.
Nepal was once a close ally, but after India encouraged a punishing trade blockade in 2015, Nepal drifted closer to China.
To the south, deep in the tropics, the Chinese have taken over an island in the Maldives, a few hundred kilometres off India's coast. Indian military experts say China has brought in millions of kilograms of sand, expanding the island for possible use as an airstrip or submarine base.
"Obviously, the Chinese aim is to pressurise India," said Mr D.S. Hooda, a retired general in India's army.
China's Foreign Ministry has blamed India for the recent tensions, but tried to play down the confrontation.
That is in stark contrast to similar border skirmishes in 2017, when the two countries squared off for 73 days over another contested Himalayan border region near Bhutan, leading to a dangerous spike in nationalistic sentiment on both sides.
"The Chinese border troops are committed to upholding China's territorial and sovereignty security, responding resolutely to India's trespassing and infringing activities and maintaining peace and tranquillity in the China-India border areas," a spokesman, Mr Zhao Lijian, said after the first public reports of clashes emerged in mid-May.
He urged India to "refrain from taking any unilateral actions that may complicate the situation".
Both countries run patrols along the disputed border, known as the Line of Actual Control, the precise location of which can be blurry.
The packs of soldiers marching up and down the mountains are under strict orders not to shoot at each other, security analysts said, but that doesn't stop them from throwing rocks. Or the occasional punch.
Sometimes, big passing patrols collide. A few years ago, another Indo-Chinese brawl broke out - and was captured on video - at the same mountain lake where some of the recent clashes happened.
China has not officially acknowledged any recent deployment of forces to the Himalayas. But a May 18 article in Global Times, a tabloid controlled by the Communist Party, cited a source close to the People's Liberation Army who said China's military bolstered its forces in response to what it considered illegal construction by India in or near Chinese territory.
China has a superior military, which analysts believe could force India to back down.
Mr Ajai Shukla, a former Indian army colonel, estimated that China had brought in three brigades of the People's Liberation Army - amounting to thousands of troops - and India had deployed around 3,000 reinforcements.
"If they want to evict the Chinese, the Indian army would have to start a shooting war," Mr Shukla said.
He doesn't think that will happen and added that India's options are "limited by not wanting this to escalate".
Just a few months ago, Mr Modi and Mr Xi were sipping fresh coconuts together during a quick summit meeting in southern India.
A good relationship would help both countries in their aspirations for world power.
Still, they have become increasingly watchful of each other, especially in the high Himalayas, where few ever go.
India has recently stepped up efforts to improve the roads its military uses to crisscross the mountain passes in the Ladakh region, on the border of Tibet.
These roads are not easy to build. They snake across a gravelly landscape of high-altitude rivers, glaciers and passes at 5,180m above sea level.
Analysts said that China did not intend to start a war, but that it wanted to frustrate India's road-building efforts.
The race to make these high mountain roads is becoming increasingly fraught. The 2017 standoff between India and China began when Indian troops physically blocked a Chinese road crew in a disputed region claimed by Bhutan, a close ally of India's.
China is also sensitive about the Indian border because it abuts two regions within China that Beijing is especially concerned about: Tibet and Xinjiang.
The spark of the recent tensions seems to have been one particular new road that the Indians have been building to reach a military airstrip at India's northernmost border outpost, which was the site of another border standoff in 2013.
The two countries have established mechanisms for resolving border conflicts since 1962, when they went to war in the Himalayas, with India losing badly.
"There hasn't been a shot fired in years," Dr Madan said, adding that the last death from a border skirmish happened in 1975.
Still, tensions could easily flare.
"All of this is happening in the area where they fought in the '62 war," she said. "There is a lot of baggage associated with this on both sides."