China elevates Arunachal claim to ‘core interest’, US warns of new flashpoint in India-China ties

China has elevated its territorial claims over Arunachal Pradesh to the level of its “core interests,” placing the northeastern Indian state alongside Taiwan, according to a recent report submitted by the US Department of Defense to the US Congress. 

The assessment suggests that Arunachal Pradesh could emerge as a major future flashpoint in India–China relations, even as the two sides have recently disengaged troops along parts of the Line of Actual Control (LAC) in eastern Ladakh.

The Pentagon report notes that China’s claims over Arunachal Pradesh, Taiwan and its maritime assertions in the South China Sea are central to Beijing’s long-term objective of achieving what it calls the “great rejuvenation” of the Chinese nation by 2049. As part of this goal, the report states, China aims to operate at a higher global level and build a “world-class military” capable of fighting and winning wars.

India, for its part, has consistently rejected China’s claims, maintaining that Arunachal Pradesh “was, is, and will always be” an integral part of the country.

While India and China reached an agreement last year to disengage forces in eastern Ladakh after years of military standoff, recent developments indicate renewed friction over Arunachal Pradesh. Tensions resurfaced last month after an Indian citizen, Prema Thongdok, was detained for nearly 18 hours during a layover in Shanghai while travelling from London to Japan. According to Thongdok, Chinese officials claimed her passport was invalid because it listed her birthplace as Arunachal Pradesh. She was allegedly denied food and basic airport facilities before being allowed to continue her journey after intervention by the Indian consulate.

Earlier this week, a YouTuber was also reportedly detained in China after referring to Arunachal Pradesh as an integral part of India in a video made in support of Thongdok.

Beijing claims Arunachal Pradesh as part of China, referring to it as southern Tibet or Zangnan, and rejects the McMahon Line drawn in 1914 by the British and then-independent Tibet as the boundary. While China initially laid claim only to the Tawang region, it later expanded its claim to the entire state. In recent years, Beijing has periodically released lists of Chinese names for locations in Arunachal Pradesh, a move seen by New Delhi as an attempt to exert political and psychological pressure.

A former Indian diplomat described the US report’s focus on Arunachal Pradesh as significant. Mahesh Sachdev told ANI that while the US had previously documented developments in Ladakh in detail, it had largely remained silent on Arunachal. Its acknowledgement now, he said, reflects growing American awareness of the tactics China employs to pressure India in the eastern sector.

The Pentagon report also flagged concerns for India regarding China’s broader regional strategy. It said the easing of tensions along the LAC should be viewed as part of Beijing’s long-term dual approach—maintaining tactical calm on the border with India while exerting sustained military pressure through Pakistan. The report cited the extensive use of Chinese-made weapons and air defence systems by Pakistan during Operation Sindoor as an example of this strategy, even though the performance of those systems came under question.

According to the report, by keeping the LAC relatively stable, China is also attempting to stabilise ties with India and limit New Delhi’s strategic alignment with Washington, even as it continues to assert its core interests elsewhere.