NEW DELHI (AFP) - A female Indian diplomat at the centre of a row with the US over her arrest in New York has revealed how she broke down after enduring "repeated handcuffing, stripping and cavity searches".

Ms Devyani Khobragade was arrested last Thursday as she dropped her children at school, sparking fury in India, which branded the incident humiliating and prompting reprisals against US officials in India.

In an email to colleagues, Ms Khobragade said she repeatedly told arresting authorities that she had diplomatic immunity only to suffer repeated searches as well as being jailed with "common criminals".

"I must admit that I broke down many times as the indignities of repeated handcuffing, stripping and cavity searches, swabbing, in a hold up with common criminals and drug addicts were all being imposed upon me despite my incessant assertions of immunity," she said in the email published on the Times of India's website on Wednesday.

"I got the strength to regain composure and remain dignified thinking that I must represent all of my colleagues and my country with confidence and pride," she said.

In the email, Ms Khobragade implored the Indian government to ensure her safety and that of her children and preserve the dignity of the Indian diplomatic service which was "unquestionably under siege".

Ms Khobragade was detained for allegedly underpaying her domestic helper who is also an Indian national and for lying on the helper's visa application form.

The comments came as the US State Department said the escalating row should not be allowed to damage ties between India and the United States.

State Department deputy spokesman Marie Harf admitted it was a sensitive issue but insisted it was a "separate and isolated incident" which should not "be tied together" and allowed to affect broader US-Indian ties.

India on Tuesday launched a series of retaliatory measures, including a demand for US consular officials return identity cards that speed up travel into and through India.

The case has dominated the Indian press, which on Wednesday hailed the government's tough stand against an "arrogant America".

"In rare display of aggression, government hits back at US for humiliating diplomat," a front-page headline in the Times of India said.