Beijing says Arunachal Pradesh, which it calls Zangnan, is a part of South Tibet - a claim New Delhi has repeatedly dismissed. China similarly ratcheted up tensions a year ago by giving Chinese names to 11 locations in the state.
Troops of the nuclear-armed neighbours engaged in minor scuffles along their disputed frontier in the state in Dec. 2022, and tensions eased after extensive military and diplomatic talks.
Yet the state is frequently the cause of friction between the Asian giants whose ties have nosedived since a bloody border clash between their troops in the western Himalayas in 2020.
China, in a statement on Saturday, said it had standardised the names of about 30 places in what it calls South Tibet, "in accordance with the relevant regulations on place name management of the State Council".
"Assigning invented names will not alter the reality that Arunachal Pradesh is, has been, and will always be an integral and inalienable part of India," foreign ministry spokesperson Randhir Jaiswal said on Tuesday.
"If I change the name of your house, does it become my house?" he said.
Last month, following a visit by Prime Minister Narendra Modi to the state to inaugurate infrastructure projects, China said it was opposed to his activities in the region. India termed the arguments "baseless".
The US also weighed in on the issue, saying it recognised Arunachal Pradesh as Indian territory and "strongly opposed" any unilateral attempts to make claims on it by military or civilian "incursion or encroachments".
China had opposed these remarks, saying the matter "has nothing to do with the US".
India and China share a 3,800 km (2,400 miles) border - much of it poorly demarcated - over which they also fought a bloody war in 1962.
Twenty Indian soldiers and four Chinese troops were killed in hand-to-hand combat in 2020, prompting both countries to fortify positions and deploy extra troops and equipment along the border.
India's foreign ministry said on Tuesday that China was making "absurd claims" over Arunachal Pradesh, adding that the northeastern state which shares a border with China will always be an "integral and inalienable part of India".
China claims Arunachal Pradesh to be a part of southern Tibet. New Delhi rejects the claim, saying Arunachal Pradesh has always been a part of India.
"Repeating baseless arguments in this regard does not lend such claims any validity," Randhir Jaiswal, India's foreign ministry spokesperson said on Tuesday.
He was responding to last week's comments made by Senior Colonel Zhang Xiaogang, spokesman of China's Ministry of National Defense, days after Indian Prime Minister Narendra Modi inaugurated a road tunnel in Arunachal Pradesh on March 9
Zhang said in a statement that India should "stop taking any moves that complicate the border issue and earnestly maintain peace and stability in the border areas", adding that the tunnel's inauguration "runs counter to the efforts made by both sides to ease the border situation".
The nuclear-armed neighbours share a 3,000-km (1,860 mile) frontier, much of it poorly demarcated. At least 20 Indian soldiers and four Chinese troops were killed in 2020 in clashes along their border in the western Himalayas.
The militaries of both countries have fortified positions and deployed extra troops and equipment along the border since those clashes. Both sides fought a border war in 1962.
