The Federal Bureau of Investigation (FBI), which is helping Indian intelligence agencies and police in probing the Mumbai terror attack, has sought permission from New Delhi to interrogate more persons in its custody.

"The FBI continues its investigation in Mumbai attack and has asked to interview other individuals in Indian custody who may be able to provide critical information on attack planning and group leadership," Donald Van Duyn, Chief Intelligence Officer, Directorate of Intelligence, National Security Branch of FBI said in his testimony before Senate Committee on Homeland Security and Governmental Affairs.