The Muslim militant group Indian Mujahedeen claimed responsibility for the blasts, CNN reported. The broadcaster said its sister network in India, CNN-IBN, received a warning e-mail five minutes before the first blast.
Indian authorities said there were at least five explosions in the assault, which targeted New Delhi's Karol Bagh market, Kailash Market and Connaught Place, a popular tourist destination. New Delhi Police spokesman Rajan Bhagat told CNN two more bombs were discovered near Connaught Place and a movie theater.
Indian Home Minister Shri Shivraj Patil characterized the attackers as "anti-national elements" who "have been trying to disturb peace and create panic among the people in various parts of the country."
In a written statement, he said: "The government will continue to deal firmly with such elements. I am confident that security agencies will soon be able to get to the bottom of these incidents and the culprits will be brought to book."