In a message to Tamil Nadu Governor K. Rosaiah, Mukherjee said: "I am saddened to learn about the tragic loss of life and injuries caused to innocent travellers in the explosions. Such senseless acts of violence deserve the strongest condemnation."
A young woman working in an IT company was killed when two bombs exploded in two coaches of a train after it entered the Chennai Central station.
"The blast highlight the desperation and cowardice of those responsible"
"No efforts should be spared in bringing the perpetrators of this heinous attack to justice. I am confident that the state government and other agencies will do the needful to provide all possible aid to the affected families," the president added.
Prime Minister Manmohan Singh said such acts "highlight the desperation and cowardice of those responsible".
"Such barbaric acts targeting innocent men, women and children only highlight the desperation and cowardice of those responsible."
Offering his condolences to the family of the deceased and heartfelt sympathies to those injured, Singh said he was "confident that the people of India will stand united against these attempting to disturb peace and harmony and urged the people to maintain peace".
"No efforts should be spared to bring the perpetrators to justice," he said.