New Delhi, Jan 22 (IANS): The transfer of 20 CBI officials was aimed at "cleansing the system" and fill the vacancies in the branches of the agency investigating important cases, said a top agency source.

The source said Monday's transfer of 20 officials was aimed at "strengthening internal vigilance" and maintain "checks and balances" within the agency system. "This exercise could continue further," he said.

Interim CBI Director M. Nageshwar Rao on Monday cleared these transfers three days ahead of a slection committee meeting on January 24 to deliberate on the appointment of the new CBI chief post Alok Verma. The selection committee is headed by Prime Minister Narendra Modi and includes Chief Justice Ranjan Gogoi and leader of the single largest opposition party in Lok Sabha, the Congress.

Officials transferred on Monday night included the investigating officer of the case probing the Rs 13,500-crore Punjab National Bank (PNB) involving fugitive diamentaire Nirav Modi and Mehul Choksi of the Gitanjali group.

According to an official order, S.K. Nair, who was posted in banking, securities and frauds branch in Mumbai and was investigating the case against Nirav Modi and Choksi, was transferred to Anti Corruption Branch, Mumbai.

Nair has been replaced by A. Saravanan, an superintendent of police from Chennai, who was probing the Sterlite protest case. The order said that Sarvanan would continue to look after the Sterlite protest case, in which 13 people died last year.

The agency has also transferred the investigation officer of the 2G scam case, Vivek Priyadarshi.

Priyadarshi, who was posted in the ACB Delhi was transferred to Chandigarh.

The transfer order also stated that all the officers who have been directed to supervise, investigate or enquire into any case or matter by a court, will continue to do so.