NEW DELHI — Three Indian soldiers were killed in clashes with Chinese troops high in the Himalayas, the Indian army said Tuesday, marking the most serious conflict between the two nuclear-armed neighbors in decades.

The deaths occurred in the mountainous region of Ladakh where India and China share a disputed — but largely peaceful — border. No Indian soldiers have been killed in clashes on the frontier between the two countries since 1975, experts say.

An officer and two soldiers died during a “violent faceoff” late Monday that caused “casualties on both sides,” the Indian Army said in a statement. It did not say how they were killed.

Senior military officers from both countries are meeting to “defuse the situation,” the army added.

Chinese Foreign Ministry spokesman Zhao Lijian did not confirm any Chinese casualties at a news briefing Tuesday.

Zhao told reporters that Indian troops had twice crossed the Line of Actual Control, the unofficial border that divides the two countries. He accused India of “provoking and attacking Chinese personnel, which led to serious physical conflicts between the two sides.”

The clashes come at a time when China is flexing its muscles across the region amid a global pandemic. In recent weeks, it has confronted Malaysian and Vietnamese vessels in the South China Sea and twice sailed an aircraft carrier through the Taiwan Strait.

India and China fought a brief war in 1962 and the border between them remains unresolved. Since May, India and China have been embroiled in tensions at several spots along the border. Soldiers engaged in skirmishes using rocks and sticks and dozens were injured, according to Indian media reports.

The tensions are especially intense at several points in Ladakh, a territory high in the western Himalayas. Analysts say that it is common for both countries to send patrols up to their respective claim lines and retreat, which sometimes leads to altercations.

But while both governments have remained tight-lipped, what has occurred in recent weeks is of a different nature. Chinese troops have crossed several kilometers into territory that India claims at several points, according to analysts and media reports. In particular, reports say, they have occupied an area in the Galwan River valley that overlooks a strategically crucial road for India.

Monday night’s deadly clashes took place in the Galwan valley, the Indian Army said.

“You’re in a very, very serious situation here,” said Ajai Shukla, an Indian defense analyst and former army officer who has written about the tensions. “This could go any which way.”

Hu Xijin, editor of the nationalist state-run newspaper the Global Times, said on Chinese-language Weibo that his sources told him there had been Chinese casualties in the clash, but he did not specify if there were any deaths or give further details.

“I want to tell Indians: do not misjudge China’s restraint as weakness, and never be arrogant before China,” he said. “China does not want conflict with India, but it is never afraid of conflict.”

Song Zhongping, a Chinese military analyst and former lecturer at the People’s Liberation Army Rocket Force University of Engineering, accused India of engaging in premeditated escalations “to distract from their domestic political situation.” China needs to “try the best methods to resolve the issue by diplomatic means, but also prepare militarily for the worst outcome.”

Earlier this month, the Chinese military staged a drill that moved thousands of paratroopers “within hours” from central Hubei Province to a remote Himalayan mountain range. The exercise, which was publicized by the PLA, was designed to send a message that China was able to rapidly deploy reinforcements to the Indian border and fight in low-temperature and low-oxygen conditions, according to state media.

Indian analysts said that China’s actions were another sign of its aggressive intentions in the region. There is a “new edge” to China’s attitude, said Nirupama Rao, a former Indian ambassador to China. “This assertiveness, this readiness to throw [away] internationally accepted behavior to advance their claims and interests, it’s worrisome for so many countries.” — Agencies