Ahead of Prime Minister Narendra Modi's trip to Beijing next month, China has described the "huge dispute" Arunachal Pradesh as an "undeniable fact."
Arunachal Pradesh shares a 1,126 km border with China and 520 km border with Myanmar. China claims Arunachal Pradesh as part of southern Tibet, a stand firmly refuted by India.
"There is a huge dispute in the eastern border of China-India border. This is an undeniable fact," said a spokesperson for the Chinese Foreign Ministry today.
In February, China issued a strongly-worded statement and lodged an official protest against PM Modi's visit to Arunachal Pradesh.
Last year, Chinese President Xi Jinping's visit to India for talks with Mr Modi was overshadowed by a massive stand-off between Chinese and Indian troops in Ladakh. Both leaders vowed to work together to resolve the border row that has defied a solution after 18 rounds of high level talks over the last decade, the most recent of which was held late last month in Delhi. Ajit Doval, the National Security Advisor, led the negotiations for India.
China lays claim to more than 90,000 sq km (35,000 square miles) of Arunachal Pradesh. India says China occupies 38,000 square km (14,600 sq miles) of its territory on the Aksai Chin plateau in the west, which was annexed by China in the 1962 war.