US Defence Secretary Chuck Hagel has expressed regret to a professor of Indian descent after he appeared to jokingly ask if the academic was a member of the Taliban.
Hagel's spokesman said on friday that the off-hand remark, which came after a speech by Hagel at the University of Nebraska on Wednesday, was not meant to refer to anyone in the audience or to the professor's heritage.
After discussing prospects for talks with the Taliban insurgency at the event and waiting for another question, Hagel pointed to the back of the hall, and said: "OK, so who has a - way up in the back there. You're not a member of the Taliban are you?"
The video did not show who he was referring to, but the question that followed his remark came from a man who introduced himself as Robin Gandhi, an assistant professor at the university.
Hagel's apparent attempt at humour appeared to fall flat, judging by the long pause that followed, according to a video of the event broadcast by the Pentagon channel.
"This was an off the cuff remark not directed at anyone in particular in the audience, and he recognises that even though it was a joke that it was perhaps off-key," press secretary George Little told reporters on Friday.
"I would emphasise it was completely unintentional and not directed at anyone in particular."
Although the Pentagon maintained Hagel was not aiming his remark at anyone, the defence secretary called the academic afterwards to express regret, Little said.
"Secretary Hagel did reach out to the professor a few hours after the speech and had a very good discussion," he said.
"He wanted to leave no impression that this joke was directed at anyone in particular, including the professor."
Asked if Hagel apologised, Little said: "He expressed regret for any trouble that this caused to the professor."
Gandhi, an assistant professor of information assurance who received his bachelor's degree from Sardar Patel University in Gujarat, India, issued a statement saying he was honoured for a chance to ask the Pentagon chief a question.
"I was able to ask a question, and I thoroughly enjoyed hearing his answer. Before I rose to ask a question, there was apparently some confusion that did not involve me," his statement said.