Noted Pakistani singer Rahat Fateh Ali Khan was detained at Delhi International Airport on Sunday evening by revenue intelligence sleuths for allegedly carrying a huge amount of undeclared foreign currency. Khan, who is a hit Bollywood playback singer, arrived on a flight from Karachi and was intercepted by personnel from Directorate of Revenue Intelligence acting on some prior information, official sources said. They said the singer was carrying a huge amount of foreign currency which he did not declare to the immigration authorities. Two other persons accompanying him have also been detained, the sources said. Khan is being questioned and the amount of the money is being ascertained, they said. Khan has several hit numbers to his credit and had won the Filmfare Award for Best Male Playback Singer this year for Dil To Bachcha Hai Ji from the movie Ishqiya.