U.S. Defense Secretary Chuck Hagel has expressed regret to an Indian-born college professor for jokingly asking, "you're not a member of the Taliban, are you?" seconds before the professor rose to ask a question.

Hagel's spokesman said the joke was not directed at anyone in particular, and the defense secretary called the professor, Robin Gandhi, to tell him as much hours after the Wednesday event at the University of Nebraska, where Hagel gave a speech and took questions from the audience.

Still, the remarks have drawn considerable media attention, particularly given the announcement this week that the United States and the Taliban intend to hold talks after nearly 12 years of war in Afghanistan.

Hagel "expressed regret for any trouble that this caused the professor," spokesman George Little told reporters.

"They had a very good discussion and (Hagel) wanted to leave no impression that this joke was directed at anyone in particular, including the professor," Little said. He noted that the defense secretary a little earlier in the program had answered a question about the Taliban, the Afghan insurgent group.

Gandhi said in a statement distributed by the university that he was honored to hear Hagel's speech and enjoyed the secretary's answer to his question about cyber weapons.

"Before I rose to ask a question, there was apparently some confusion that did not involve me," Gandhi said, suggesting he too did not believe Hagel's joke was addressed at him.

Nothing in the video of the event suggests Hagel knew Gandhi would be the next person to ask a question when he made the joke 12 seconds earlier.

Gandhi is an assistant professor of information assurance at the University of Nebraska's College of Information Science and Technology. A university spokesman said Gandhi was born in India.