Prime Minister Manmohan Singh has strongly condemned the serial blasts in the national capital and appealed to the people to maintain calm.
Indian Mujahideen claims responsibility
He expressed grief over the loss of lives in blasts, a Prime Minister's Office spokesman said.
President Pratibha Patil termed the serial blasts in the national capital as a 'mindless act of violence' and appealed to the people to maintain peace.
Patil condoled the loss of lives in the explosions and described the incident as a 'mindless act of violence', a Rastrapati Bhavan statement said.
PM is a failure on national security: Advani
The President has been grieved by the tragic turn of events, it said.
Patil also wished the speedy recovery to those injured in the blasts.
Lok Sabha Speaker Somnath Chatterjee too strongly condemned the serial blasts in the capital and expressed grief at the loss of lives.
Chatterjee expressed strong indignation at the explosions and sent his heartfelt condolences to the members of the bereaved families.
Congress President Sonia Gandhi has described the Delhi serial blasts in Delhi as "dastardly" and an "act of cowardice".
She said those behind the blasts will not be spared and they have no place in civilised society.
The Delhi blasts of 2005
Complete coverage: The Ahmedabad blasts
Coverage: The Bengaluru blasts
Coverage: The Jaipur blasts
The Hyderabad blasts of 2007