China on Monday said it lodged a diplomatic protest with India over Prime Minister Narendra Modi’s visit to Arunachal Pradesh last week, reiterating its claim over the area by saying India's moves will "only complicate" the boundary question.

Prime Minister Modi on Saturday dedicated to the nation the Sela Tunnel built at an altitude of 13,000 feet in Arunachal Pradesh that will provide all-weather connectivity to strategically located Tawang and is expected to ensure better movement of troops along the frontier region.

The Rs 825 crore tunnel, constructed on the road connecting Assam's Tezpur to West Kameng district of Arunachal Pradesh, is being billed as the longest bi-lane road tunnel in the world at such an altitude.

The Sela Tunnel will provide for better movement of troops and weaponry to various forward locations along the Line of Actual Control (LAC) with China, according to military officials.

China, which claims Arunachal Pradesh as South Tibet, routinely objects to Indian leaders' visits to the state to highlight its claims. Beijing has also named the area as Zangnan.

India has repeatedly rejected China’s territorial claims over Arunachal Pradesh, asserting that the state is an integral part of the country. New Delhi has also dismissed Beijing's move to assign "invented" names to the area, saying it did not alter the reality.

Asked by the official media about Modi’s visit to Arunachal Pradesh at a media briefing here on Monday, Chinese Foreign Ministry spokesperson Wang Wenbin said “Zangnan area is Chinese territory”.

"China never recognised the so-called Arunachal Pradesh illegally set up by India and firmly opposes it," he said.

The China-India boundary question has yet to be resolved. India has no right to arbitrarily develop the area of Zangnan in China, he said.

“Relevant moves by India only complicate the boundary question. China is strongly dissatisfied with and firmly opposed to the leader’s visit to the eastern section of the China-India boundary," he said.

“We have made solemn representations to India," Wang added.

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