China, which claims Arunachal Pradesh as South Tibet, said it "strongly deplored" PM Modi's last week's visit and India's move would "only complicate" the boundary issue.

"We reject the comments made by the Chinese side regarding the visit of the Prime Minister to Arunachal Pradesh. Indian leaders visit Arunachal Pradesh from time to time, as they visit other States of India," External Affairs Ministry spokesperson, Randhir Jaiswal, said in a statement released on Tuesday.

Asserting that objecting to such visits or India's developmental projects does not stand to reason, Jaiswal said: "It will not change the reality that the State of Arunachal Pradesh was, is, and will always be an integral and inalienable part of India".

The Spokesperson further added that the Chinese side has been made aware of "this consistent position on several occasions".

Following PM Modi's visit, Chinese Foreign Ministry spokesperson Wang Wenbin said at a media briefing that Beijing "never recognised the so-called Arunachal Pradesh illegally set up by India and firmly opposes it".

"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," Wenbin had said.

Situated at an altitude of 13,000 feet, the Sela Tunnel -- the world's longest twin-lane tunnel -- was inaugurated by PM Modi in Arunachal Pradesh on March 9.

The strategically important tunnel will ensure all-weather connectivity to Tawang in Arunachal Pradesh.