The major operation by the investigation wing of the Mumbai Income Tax department on the diamond companies based at the Bharat Diamond Bourse (BDB) at Mumbai's Bandra-Kurla Complex (BKC) on Monday has rocked the world's biggest diamond cutting and polishing centre in Surat.

Around 17 companies are learnt to have been raided at the BDB by Mumbai's I-T department.

Sources said that the Mumbai I-T department has swooped down on more than 17 diamond companies located at BDB. The search and seizure operation was extended to the Mahidharpura diamond market in Surat where some of the diamond firms in Mumbai have their offices and units.

More than 60 I-T personnel along with the team of 100 police personnel swooped down at BDB in Mumbai on early Saturday morning. One of the diamond firm is believed to have declared Rs 11 crore and that the I-T officials have seized documents, cash and jewellery from the offices and residences of the diamantaires.

Official sources in Surat's I-T department said that the raid has been extended to Surat's Mahidharpura diamond market as well. Also, the residence and the offices of other diamantaires are likely to be searched in a day or two.