Congress MP Karti Chidambaram appeared before the Enforcement Directorate on Tuesday for a fresh round of questioning in a money laundering case linked to issuance of visas to some Chinese nationals in 2011, official sources said.

The 52-year-old legislator from Sivaganga Lok Sabha seat in Tamil Nadu was questioned in this case on December 23 last year and the central agency recorded his statement under the provisions of the Prevention of Money Laundering Act (PMLA).

He again deposed before the investigating officer of the case at the ED headquarters in central Delhi, officials said.

"This is a routine affair. These are things that happen routinely especially when elections come near. These are all exercises in futility. We will go through them," he told reporters before going inside the agency's office.

The money laundering case, filed under the provisions of the Prevention of Money Laundering Act (PMLA), stems from a CBI FIR.

The probe 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, according to the Central Bureau of Investigation (CBI) FIR.

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 CBI had last year raided the premises of the Chidamabram family and arrested Bhaskararaman even as Karti was questioned by it.

Karti has earlier said that the ED probe was a "fishing and roving" enquiry and that he has submitted documents to the agency in the past. He had called the case "most bogus", asserting he was "certain that he never facilitated even a single Chinese national in their visa process, let alone 250." He had said this case an attempt to target his father (senior Congress leader P Chidambaram) through him.

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