Right-wing Indian Hindu activists wearing masks of US President Barack Obama take part in a protest near the US Embassy in New Delhi on Wednesday. Photo: AFP

India vowed Wednesday to bring one of its diplomats home at any price after her arrest in New York, as she told how she broke down in tears after being stripped and cavity-searched.

As a leading daily hailed the government for "taking on Uncle Sam," Foreign Minister Salman Khurshid pledged to "restore the dignity" of the diplomat - whose treatment at the hands of a superpower has touched a raw nerve in India.

Khurshid's promise came a day after India announced a series of reprisals and despite an overnight plea by the US State Department not to allow the row to damage relations.

"It is my duty to bring the lady back," Khurshid told lawmakers.

"We have to restore her dignity and I will do it at any cost," he added in the highest-level intervention by an Indian official since deputy consul general Devyani Khobragade was arrested last Thursday.

Indian Prime Minister Manmohan Singh then further stoked the furor by calling her arrest "deplorable" in brief comments reported by the Press Trust of India.

The US Marshals Service confirmed on Tuesday that Khobragade, 39, had been strip-searched like other prisoners after being detained while dropping her two children off at school.

US authorities say she not only paid a domestic servant a fraction of the minimum wage but also lied in a visa application for the employee, an Indian national who has absconded.

In an e-mail to colleagues published Wednesday, Khobragade said she told arresting authorities that she had diplomatic immunity - only to suffer repeated searches and to be 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 e-mail.

The revelation that a high-ranking diplomat could be subjected to such treatment while on a posting to the US has caused huge offence in a country that sees itself as an emerging world power.

US State Department deputy spokeswoman Marie Harf admitted the arrest was a "sensitive issue" but insisted it was a "separate and isolated incident" which should not be allowed to affect broader ties.