What should the person praying behind an imam do if he recites a verse in which there is a sajdah (prostration)?
Question

                What should I do if I recite a soorah in which there is a sajdah when I am praying behind an imam?.
Praise be to Allah.
    You should not prostrate, because following the imam is 
    obligatory and the prostration of recitation is Sunnah. If a person is 
    praying behind an imam, it is not permissible for him to prostrate, and if 
    he prostrates deliberately although he knows that that is not permissible, then his prayer becomes invalid. End quote.