India has accused Chinese soldiers of launching an incursion far into Indian territory, the latest flare-up of tension between the two Asian giants over their de facto boundary in the Himalayas.

"Chinese troops entered 10km into Indian territory on April 15 and pitched tents in the Depsang valley in the Ladakh region of eastern Kashmir," an Indian official said on Tuesday.

Indian army commanders have met at least two times with their Chinese counterparts, but Chinese troops remain in Indian-claimed territory, said Tsering Angchuk, a civil administrator in Ladakh. "They have not vacated the position so far,'' he said.

India's foreign ministry said it had asked China to withdraw troops from the territory.

"We have asked the Chinese side to maintain the status quo in this sector [of the western border]," spokesman Syed Akbaruddin told a briefing. "By this I mean the status quo prior to this incident."

China dismissed reports of an incursion as Indian media speculation and said the border region has been peaceful.

"The two parties have maintained good communication and coordination on the border issue,'' Chinese foreign ministry spokeswoman Hua Chunying said on Tuesday.

A day earlier, Hua said Chinese troops had "patrolled the border line and did not go one step across the Line of Actual Control,'' the unofficial boundary between the two countries.

India says Chinese troops have repeatedly crossed the boundary in recent years, leaving trash with Chinese markings as evidence of their presence.

However, Indian officials said the new incursion was far deeper into Indian-claimed territory than before.

Indian foreign secretary Ranjan Mathai filed a protest over the incursion with the Chinese ambassador last week, an external affairs ministry official said on condition of anonymity because he was not authorized to speak to the media about the sensitive subject.

Indian defense minister AK Antony said Monday that "India will take every step to protect its interests.'' He did not elaborate.

Chilly relations

India and China, neighbors with more than 1bn people each, have had chilly relations since they fought a border war in 1962.

China claims around 90,000 square kilometres of land in India's northeastern state of Arunachal Pradesh, while India says China is occupying 38,000 square kilometres of territory in the Aksai Chin plateau in the western Himalayas.

The two sides have held 15 rounds of talks to resolve their border dispute, without making much progress.

China is a longtime ally and weapons supplier to Pakistan, India's bitter rival.

The presence in India of the Tibetan spiritual leader the Dalai Lama and the self-declared Tibetan government-in-exile also remain a source of tension between New Delhi and Beijing. China is also suspicious of New Delhi's growing ties with the United States.

Despite the territorial tensions, trade between India and China has soared, with China becoming India's biggest trading partner.

Two-way trade jumped from $5bn in 2002 to nearly $75bn in 2011, but declined slightly last year because of the global economic downturn. But it remains heavily skewed in China's favor, another source of worry for India.