NEW DELHI: Strongly condemning the blast in Hyderabad, Congress president Sonia Gandhi on Friday expressed her condolences to the bereaved families in the "senseless act".

Gandhi, in a message, also asked Andhra Pradesh Chief Minister Y S Rajasekhara Reddy to take immediate steps so that those responsible are brought to the book.

She also expressed "deep concern and grief" over the incident.

At least five persons were killed and eight others, including two children, were injured when a powerful bomb exploded during Friday prayers at the historic Mecca mosque in the Charminar area of the old city in Hyderabad on Friday afternoon.