The United States has expressed regret over India's ambassador Meera Shankar being pulled out of an airport security line and frisked by a security agent.
Secretary of State Hillary Clinton said she was concerned about the incident and vowed to prevent a recurrence.
The hands-on search took place even after Meera Shankar's diplomatic status was revealed. Some reports said Shankar, who was on her way from a conference, was singled out as she was wearing a sari.
The search took place on December 4th, 2011 at the Jackson-Evers International Airport. Shankar was about to board a flight to Baltimore after attending an event at Mississippi State University.
The Indian embassy in Washington strongly protested about the incident and External Affairs Minister SM Krishna called it "unacceptable".
"We obviously are concerned about it," Mrs Clinton told reporters. "We will be looking into it and trying to determine both what happened and what we could do to prevent such incidents in the future."
US Homeland Security Secretary Janet Napolitano, however, said officials had handled the matter "by the book".
"It was a pat-down that followed our procedures, and I think it was appropriate under the circumstances," she told reporters.
Recently there was outrage in India when Bollywood superstar Shah Rukh Khan was detained in New York for over 90 minutes by US authorities at White Plains airport near New York.
The actor arrived on a private plane and was on the way to Yale University for a function when he was stopped.
US customs and border protection authorities later expressed "profound" apologies for the incident.
The spokesman for the US embassy in Delhi, Peter Vrooman, also apologised "if Mr Shah Rukh Khan experienced an inconvenience or delay".
It is not clear why Khan was detained at the airport.
In 2009 the actor was detained for two hours at Newark airport and was released after India's embassy in the US intervened.
The actor said then that he was stopped because he had a Muslim name. US customs officials denied that Khan had been detained, saying he was questioned.
He was freed after Yale University officials contacted homeland security and customs officials, reported the BBC.
Later, he told the students of Yale University that he had been stopped and questioned at the airport.
"Whenever I start feeling arrogant about myself, I always take a trip to America. The immigration guys kick the star out of stardom," he said to laughter from the audience.
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.