India's ambassador to US has been pulled from an airport security line and frisked by a security agent in Mississippi, it has emerged.
The hands-on search took place last week even after Meera Shankar's diplomatic status was revealed.
Some reports said Ms Shankar, who was on her way from a conference, was singled out because she was wearing a sari.
The Indian embassy in Washington has strongly protested about the incident.
The search took place on 4 December at the Jackson-Evers International Airport, news agency Press Trust of India quoted an Indian Embassy official as saying.
Ms Shankar was about to board a flight to Baltimore after attending an event at Mississippi State University.
She was taken to a VIP waiting room despite staff being told that she was an ambassador, he said.
She was later pulled from a security line and patted down by a female Transportation Security Administration agent.
"This is unacceptable to India and we are going to take it up with the US government and I hope things could be resolved so that such unpleasant incidents do not recur," External Affairs Minister SM Krishna told reporters in Delhi.
The incident has also embarrassed the university officials who had invited Ms Shankar to give a speech.
"It was a wonderful programme, maybe the best we've had, (but) this stupid incident ruined the whole thing," Associated Press quoted Janos Radvanyi, chair of the university's international studies department as saying.
"She said, 'I will never come back here'. We are sending her a letter of apology," he said.
Last year, America's Continental Airlines apologised to former Indian president APJ Abdul Kalam for frisking him before he boarded a flight to the US.
Members of India's parliament were outraged after it emerged that Mr Kalam had been frisked and made to remove his shoes at Delhi airport in April.
Protocol exempts former presidents and other dignitaries from such searches.