Police with sniffer dogs search one of the damaged areas
Seven bombs have hit the southern Indian city of Bangalore within minutes of each other, police say.
At least two people were killed and several people injured. Police say the bombs were detonated with timers.
The blasts have been described as low intensity and all are reported to have occurred in crowded areas.
Bangalore is the information technology hub of India with more than 40% of the country's IT and software industry based there.
Malls, schools and cinema halls across Bangalore have been shut and police have cordoned off the blast sites.
RECENT BOMB ATTACKS
May 2008: Eight bombs in Jaipur kill 63
August 2007: Two bombs Hyderabad kill more than 40
May 2007: Bomb in Hyderabad mosque kills 14
February 2007: Twin blasts on train travelling from Delhi to Pakistan kills at least 66 people near Panipat
July 2006: More than 160 killed by seven bombs on train network in Mumbai
March 2006: Bombs at Hindu temple and railway station in Varanasi kill 15
October 2005: Three blasts in Delhi kill 62
"We are conducting the investigation. Bomb squads have reached the scene. We appeal to the citizens to carry on their normal activities without any fear," Bangalore city police commissioner Shankar Bidri said.
Mr Bidri said each of the explosions were of a similar magnitude to one or two grenades.
He blamed the attack on people "disturbing the peace and tranquility of Bangalore city".
There was no immediate claim of responsibility for the blasts.
The government condemned the blasts and vowed to catch those behind them.
"Such incidents will not deter the government from pursuing its policy of dealing with terrorists in a resolute manner," Home Minister Shivraj Patil said.
Police said a woman died in the explosion at Madiwala area and another person died later.
Other blasts were in the areas of Nayanadhalli, Adugudi, Rajaram Circle, Anepallya and Ashok Nagar.
At least 12 people were injured and most have been taken to Bangalore's St John's hospital.
A large part of India's IT and outsourcing business is concentrated in Bangalore.
Dozens of large international firms like Microsoft, Intel and IBM also have offices in the city which is often called the Silicon Valley of India.
There have been a number of blasts in Indian cities in recent years.
They are almost always blamed on foreign militants but there have been no significant arrests or convictions in any of the cases.