Before addressing the students at the Yale University, which is three hours from New York, Khan said, he was "detained" at the airport "as always happens".
Khan, who has been named a Chubb Fellow, was accompanied by Neeta Ambani and they were understood to have arrived in a private plane at the New York`s White Plain airport. Ambani`s daughter is a student of Yale University.
Sources told PTI, while everybody else were cleared by the immigration immediately, Khan was stopped for over two hours before being cleared by the immigration officials.
"Khan was very very upset at the episode. Yale University officials had to contact the Department of Homeland Security and the Immigration and Customs Department at Washington, when they come to know about his detention," sources said.
In 2009 also, he was stopped at the Newark airport and was released after two-hour of grilling.