VOA常速英语:Serial Explosions Hit Southern Indian City

Authorities in Bangalore are appealing for calm after seven blasts shook India's technology hub within a 15-minute period Friday afternoon.

Some officials are terming it a coordinated terrorist attack intending to cause panic. There has been no immediate claim of responsibility. Investigators on the scene told reporters the explosive devices were loaded with nuts and bolts.

The city's police commissioner, Shankar Bidri, tells reporters the blasts were triggered by gelatin sticks with timers but were of low intensity.

"Explosives also have been used in a quantity equal to one or two grenades," Bidri said. "It appears to be an act of persons who are having the mali fide (bad) intention of disturbing peace and tranquility of Bangalore city."

The police commissioner appealed to residents to go about their activities as normal. But most schools and shopping malls immediately closed for the remainder of the day as word spread of the multiple explosions.

Authorities say they have raised the state of alert in New Delhi and Mumbai, India's two largest metropolitan areas. Bangalore is India's third largest city and the country's center for outsourcing and software development. Many of the world's largest information technology companies have offices there.

Friday's explosions come little more than two months after seven bombs strapped to bicycles were detonated in the tourist destination of Jaipur outside markets and Hindu temples. That attack killed at least 63 people.

Compared to other parts of India, such acts of violence are rare in Bangalore. In late December 2005 in the city gunmen killed a professor attending an international conference on the campus of the prestigious Indian Institute of Science.