In an astonishing revelation, city police in a survey have found that 60 per cent of prepaid SIM cards were procured using fake documents here.

Besides, mobile service providers, the city police held vendors equally responsible for providing prepaid SIM cards without proper verification and cracked down on them, prompting several shops in city and suburbs to put up a notice saying "SIM Cards Not Available."

The police drive comes days after an email purportedly sent by the banned outfit Indian Mujahideen claimed responsibility for the attacks outside the historic Jama Masjid in the national capital.

Internet connection of a mobile phone that had Tata Doccomo SIM card was used to send the email soon after the attacks outside the Jama Masjid. It was not clear if either prepaid or post-paid SIM card was used to send the mail.

"It is worrying to find out that 60 per cent of the 15,000 prepaid SIM cards were issued by vendors without proper verification of documents. We have randomly taken up 15000 prepaid SIM card details and when our men verified them, this startling revelation has come to their notice," Mumbai Police Commissioner Sanjeev Dayal told PTI.

"With a target to sell more prepaid SIM cards and entail commission, the vendors cannot put the norms at bay.

They should verify the addresses and other documents provided by the card seekers," he added.

"The mobile service providers have also been asked to verify the documents of SIM card seekers properly," Dayal said.