The ED has registered a money laundering case against Congress MP Karti Chidambaram and others to probe alleged irregularities in the issuance of visas to 263 Chinese nationals in 2011 when his father P Chidambaram was the home minister, officials said on Wednesday.

The federal agency has filed its case under the criminal sections of the Prevention of Money Laundering Act (PMLA) taking cognisance of a recent first information report (FIR) registered by the CBI in the same case, they said.

The case pertains to allegations of Rs 50 lakh being paid as kickbacks to Karti and his close associate S Bhaskararaman by a top executive of Vedanta group company Talwandi Sabo Power Ltd. (TSPL), which was setting up a power plant in Punjab, the CBI FIR had said.

The Central Bureau of Investigation (CBI) had raided the premises of the Chidambaram family and arrested Bhaskararaman last week, even as Karti Chidambaram is expected to depose before it for questioning.

This is the third money laundering case against Karti Chidambaram with the INX Media and Aircel-Maxis cases being probed by the Enforcement Directorate (ED) for some years now.

The ED will probe the possible "proceeds of crime" that could have been generated due to the alleged illegal activity in the visa case, they said.

The accused involved in the case will be questioned as part of the investigation, officials said.

Fifty-year-old Karti Chidambaram, the Congress MP from the Sivaganga constituency in Tamil Nadu, has denied all allegations.

In a statement posted on his Twitter handle on Tuesday, he said "if this is not harassment, not a witch hunt, then what is."

"I have full faith in the judiciary of our great country and trust the institution to stand by the truth. It does not intimidate me that the central government is once again using its agencies to accuse me of a malicious and completely fabricated charge," he said.

"Previously, the agencies have gone after me based on the statement of an undertrial murder suspect. Now, they are basing their bogus charges on the alleged actions of a deceased person, whom I have never met. I intend to continue to fight every one of their motivated attempts to target my father through me," the Congress MP said.

He said he was "certain that he never facilitated even a single Chinese national in their visa process, let alone 250."

According to the CBI, the work for setting up the power project was being executed by a Chinese company and was running behind schedule.

A TSPL executive had sought re-issuance of project visas for 263 Chinese workers for which Rs 50 lakh allegedly exchanged hands, according to the CBI FIR.

The agency has alleged that Bhaskararaman was approached by Vikas Makharia, the then associate vice president of TSPL, for the reissue of project visas for the Chinese workers working at the Mansa-based power plant.

The CBI FIR alleged that Makharia approached Karti Chidambaram through his "close associate/front man" Bhaskararaman.

"They devised a back-door way to defeat the purpose of ceiling (maximum of project visas permissible to the company's plant) by granting permission to reuse 263 project visas allotted to the said Chinese company's officials," it was alleged.

Project visas were a special facility introduced in 2010 for the power and steel sector for which detailed guidelines were issued during P Chidambaram's tenure as the home minister but there was no provision of re-issue of project visas, the FIR alleged.

"As per prevalent guidelines, deviation in rare and exceptional cases could be considered and granted only with the approval of the home secretary. However, in view of the above circumstances, the deviation in terms of reuse of project visas is likely to be approved by the then Home Minister...," it further alleged.

The CBI, in its FIR of May 14, has named Karti Chidambaram, Bhaskararaman, Makharia, Talwandi Sabo Power Limited (TSPL), and Mumbai-based Bell Tools Limited, through which alleged bribes were routed.

The case was registered under Indian Penal Code sections 120-B (criminal conspiracy) and 477A (falsification of accounts) and sections 8 and 9 of the Prevention of Corruption Act.

Makharia allegedly submitted a letter to the home ministry on July 30, 2011, seeking approval to reuse the project visas allotted to his company, which was approved within a month and permission was issued, officials said.

It alleged that the payment of the bribe was routed from TSPL to Karti Chidambaram and Bhaskararaman through Mumbai-based Bell Tools Ltd with payments camouflaged under two invoices raised for consultancy and out-of-pocket expenses for works related to visas for the Chinese workers.

Makharia had later thanked Karti Chidambaram and Bhaskararaman in an e-mail, the CBI alleged.