New Delhi  - A curfew was imposed in large parts of the old walled city area of the northern Indian metropolis of Jaipur Wednesday, the morning after 60 people were killed and more than 150 injured in a series of bombings.

Eight bombs went off within about 20 minutes Tuesday night in an area with a 2-kilometre radius in the walled quarter, leaving a trail of death. A ninth bomb was defused, the NDTV television channel reported.

Investigations were being conducted, and forensic experts were working in the area, a police official was quoted as saying. He said preliminary investigations indicated that the explosive TNT was used in the bombs, which were planted on cycles and used alarm clocks as triggers.

"It is clearly a well-planned operation, and strangely, the state police had no intelligence information," a top intelligence officer said. "All the blasts happened when people were milling around these places."

At least two of the blasts took place near some of the city's most popular spots - a famous sweetshop cum eatery in Johari Bazaar and a temple to the monkey god Hanuman at Tripolia Bazaar, which drew its largest number of devotees on Tuesday.

Jaipur, capital of Rajasthan state and one of India's most popular tourist destinations, has no history of communal violence, but the authorities imposed a curfew as a precautionary measure.

The blasts were clearly aimed at fomenting violence between Hindus and Muslims, officials said.

The police said they suspect the involvement of the Bangladesh-based Islamic militant group Harkat-ul-Jehadi Islamia along with some local groups, NDTV reported. No one has claimed responsibility.

Anxious relatives were joined by well-wishers and blood donors at busy hospitals through the night as Jaipur rallied to deal with the tragedy.

Schools, colleges and businesses outside the walled city set about work as usual Wednesday, NDTV reported. (dpa)