Ahmedabad, July 29: Eighteen bombs were detected and defused in India’s diamond hub today, with the terrorists apparently choosing to mock the nation’s vulnerability without killing.

Alerted by ordinary people in the diamond hub of Surat, police found one bomb after another in crowded spots from morning through afternoon. Many hung from trees and hoardings 20 feet above the ground, or had been left near schools, power transformers and diamond-polishing or textile units, often with little effort to hide them.

An email sent to media offices around 11am by Indian Mujahideen — which has claimed responsibility for the weekend Bangalore and Ahmedabad blasts — said the militants had meant not to kill this time but merely to flex their muscle.

“We have full killing weapons to destroy the whole... India,” the email added.

The aim of creating panic succeeded, with schools and colleges closing by themselves or being ordered shut by the administration. The town, where three bombs had been detected in the past two days, is expected to shut down tomorrow, and even schools in four “sensitive” localities of Ahmedabad have been ordered to stay closed.

About a dozen bombs were found in and around bustling Varachha Road, the town’s diamond street and a storehouse of wealth that few areas of the country can match. Surat, 250km from Ahmedabad, is the world’s largest diamond-polishing centre with 6,000 units and nearly 10 lakh workers, and an annual business of Rs 70,000 crore.

Most of the bombs were noticed by alert passers-by who called up the police control room. Many of them were members of the Friends of Police, a citizens’ organisation that has turned into an effective news gathering agency.

Over the past two days, the police had explained through the media what a bomb might look like. Those found today were three-sided, wooden-frame structures tightly wrapped in green polythene.

Investigators said that instead of the digital-watch timers used in Ahmedabad, these bombs were fitted with “some kind of a chip” that functioned as an “integrated timer circuit”.

A three-member bomb disposal unit had its hands full, defusing one bomb (a process that takes around 15-20 minutes) and immediately rushing elsewhere to defuse another.

Amid the relief over the successful public vigilance, one question worried a senior police officer: “Only one bomb was found yesterday; how come so many mushroomed overnight?”

The email said the next targets included “(Narendra) Modi, Asharam, schools and colleges”, and named several Gujarat universities and technology institutes. “Asharam” could be a reference to chief minister Modi’s spiritual guru Asaram Bapu.