NEW DELHI/BEIJING (Reuters) – Indian and Chinese troops fought each other with iron rods and stones at their disputed border, resulting in casualties on both sides including the deaths of three Indian soldiers, Indian officials said on Tuesday, in a major escalation of a weeks-old standoff.

China blamed India for the fight in the snow deserts of Ladakh in the western Himalayas on Monday and the editor of the government-controlled Global Times also said the Chinese military had suffered casualties.

The deaths were the first since the last major border clash in 1967 between the nuclear-armed Asian giants and world’s two most populous countries who have not been able to settle the dispute along their vast frontier.

Since early May, hundreds of soldiers have faced off against each other at three locations, including along the banks of the Pangong Tso lake, each side accusing the other of trespassing.

On Monday night, a small group of soldiers came to blows in the Galwan Valley, Indian officials said, but it was not clear what had provoked them.

“During the de-escalation process under way in the Galwan Valley, a violent face-off took place yesterday night with casualties on both sides,” the Indian army said in a statement.

“The loss of lives on the Indian side includes an officer and two soldiers. Senior military officials of the two sides are currently meeting at the venue to defuse the situation.”

The officer who died was a colonel, a government source said. The two sides had been discussing ways to de-escalate but at some point the People’s Liberation Army turned on a group of Indian soldiers, the source said.

“They attacked with iron rods, the commanding officer was grievously injured and fell, and when that happened, more soldiers swarmed to the area and attacked with stones,” said the source, who had been briefed on the matter.

The Chinese side brought in reinforcements and the brawl went on for a couple of hours, the source said. No shots were fired at any stage.

A Chinese foreign ministry spokesman in Beijing said there was a serious violation of the consensus reached by the two countries when Indian troops provoked and attacked Chinese personnel.

“What’s shocking is that on June 15, the Indian side severely violated our consensus and twice crossed the border line and provoked and attacked the Chinese forces, causing a violent physical confrontation between the two border forces,” Zhao Lijian told reporters in Beijing.

“China is raising strong opposition and stern representations to the Indian side on this,” he said. There was no information provided on any casualties.

VITIATED ATMOSPHERE

India and China fought a brief but bloody border war in 1962 and distrust has occasionally led to flare-ups ever since.

Border guards have had skirmishes and fist fights when patrols have confronted each other, but there has been no loss of life at the border since 1967.

“This is extremely, extremely serious, this is going to vitiate whatever dialogue was going on,” former Indian army commander D. S. Hooda said.

Military experts say that one reason for the face-off is that India has been building roads and airfields to improve connectivity and narrow the gap with China’s far superior infrastructure.

At Galwan, India completed a road leading to an airfield last October. The Chinese side have asked India to stop all construction.

India says it is operating on its side of the Line of Actual Control, the de facto border.

The editor-in-chief of China’s Global Times newspaper said the Chinese military had suffered losses in the latest clash, though it was unclear whether those were deaths or wounded.

“Based on what I know, the Chinese side also suffered casualties in the Galwan Valley physical clash,” Hu Xijin said in a tweet. He did not give further details. The Global Times is published by the People’s Daily, the official newspaper of China’s ruling Communist Party.