Congress leaders, including Karnataka governor HR Bhardwaj, on Monday rejected the corruption allegations against the Congress president Sonia Gandhi's son-in-law Robert Vadra and the opposition parties adopted a cautious approach on the issue.

In an unusual step for a governor, Bhardwaj went public in his defence of the Nehru-Gandhi family.

"Many allegations were levelled against the Gandhi family even in the past. Indira Gandhi was also attacked. But she had a towering personality and fought back. Morarji Bhai (late PM Morarji Desai) made so many cases against her but they fell like nine pins," the former law minister said.

Congress said the attack on Vadra was "not on an individual".

"The attack by Kejriwal and Bhushan was not on an individual but on Congress and its leadership," party spokesperson Rashid Alvi said.

The CPM sought a probe into business dealings of the companies promoted by Vadra. NDA convenor and JD(U) chief Sharad Yadav, however, said the allegations appeared to be a ploy to divert attention from the larger issue of corruption.