Beijing on Tuesday denied allegations by a UK-based Indian woman that she was harassed at Shanghai airport last week because she hails from Arunachal Pradesh, which China claims as its territory.

China’s claims drew a sharp response from India, which reminded Beijing of its failure to “explain” the “violations”.

Chinese media quoted foreign ministry spokesperson Mao Ning as saying that Prema Wangjom Thongdok had undergone some “verification procedures” and faced no harassment or coercion.

The 1989-born Prema, an accounts professional in the UK, had on Sunday posted on X that while flying from London to Japan on holiday, she had been detained for over 18 hours during a layover at Shanghai airport on November 21.

Prema, who has been living in the UK for 14 years, alleged that Chinese immigration officials had declared her Indian passport “invalid” because her birthplace was Arunachal.

She claimed that despite holding a “valid visa”, she was not allowed to board the connecting flight to Japan. She was able to fly out only after the Indian consulate in Shanghai intervened, she added.

Delhi had lodged a demarché (diplomatic protest) with Beijing and in Delhi.

Sources said China on Tuesday denied the woman’s allegations while reiterating its claim on Arunachal, which Beijing calls Zangnan, as an extension of South Tibet.

A report in the South China Morning Post quoted Mao as saying that border inspection authorities had “carried out verification procedures in accordance with laws and regulations, enforced the law fairly and civilly, and fully safeguarded the legitimate rights and interests of the individual concerned”.

Mao asserted that the woman passenger was neither coerced nor detained nor harassed and that the airline had “provided the individual with a place to rest, as well as food and drinks”.

Prema had described her experience as “traumatic” and said she was not allowed to buy food.

Mao said: “Zangnan is Chinese territory. China has never recognised the so-called Arunachal Pradesh illegally established by India.”

Reacting to the Chinese foreign ministry’s response to the Shanghai airport developments, external affairs ministry spokesperson Randhir Jaiswal said on Tuesday: “We have seen statements made by the Chinese ministry of foreign affairs.... Arunachal Pradesh is an integral and inalienable part of India, and this is a self-evident fact. No amount of denial by the Chinese side is going to change this indisputable reality.

“The issue of the detention has been taken up strongly with the Chinese side. Chinese authorities have still not been able to explain their actions, which are in violation of several conventions governing international air travel. The actions by the Chinese authorities also violate their own regulations that allow visa-free transit up to 24 hours for nationals of all countries.”

Arunachal chief minister Pema Khandu expressed “deep shock” at the “appalling humiliation and racial mockery”.