In her letter to Advani written on February 15, Gandhi had said that the task force report contained "baseless and reckless allegations" and wondered how Advani could be "endorsing such scurrrillous and malicious fabrications".

"My attention has been drawn to a publication titled ’Indian black money abroad in secret banks and tax havens’ purporting to be a report submitted by a task force appointed by BJP. This so called report contains reckless and baseless allegations against me and my family including my late husband and my mother", Gandhi had noted in her communication to the BJP leader, sources said.

She had added that these "lies" energetically disseminated from time to time by sections of the media and interested parties have so far been treated by her with the contempt they deserve.

Gandhi said she was "surprised and disappointed" to find a leader of Advani’s stature endorsing such "scurrilous and malicious fabrications" through their release at a function presided over by him.

This had prompted Advani to express his "deep regret", a move which was welcomed by Congress party. However, Information and Broadcasting Minister Ambika Soni also took a dig at the BJP leader over the issue.

In a brief letter sent to Gandhi on February 17, Advani had said, "I am happy that you have denied the reports relating to you and your family alluded to in the Task Force’s Report on Black Money.

"If these had been denied earlier the Task Force would have taken your denial into account. Even so, I deeply regret the distress caused to you".

The Congress welcomed Advani’s letter but Information and Broadcasting Minister Ambika Soni took a dig at the BJP veteran, saying she thought he had retired leaving the space for younger people like Sushma Swaraj and Arun Jaitley.

"Mr Advani has been making a statement everyday on different subjects... Probably, he is not having enough time to study  what he is saying," Soni had said.

Notwithstanding Advani’s regret, the BJP said that Gandhi should have issued a rebuttal or a denial earlier as several magazines and journals had made these allegations against her family members from time to time.

The BJP appointed four-member task force comprises S Gurumurthy, former IB director Ajit Doval, Professor R Vaidyanathan from IIM-Bangalore, and advocate Mahesh Jethmalani.

The task force report, released by Advani and other NDA leaders on Feb 1, had alleged that Sonia Gandhi and former Prime Minister Rajiv Gandhi were among Indians who held Swiss bank accounts