Congress also said it would raise the issue in Parliament.
The Congress Monday demanded an independent probe into the corruption allegations made by a CBI DIG in an affidavit before the Supreme Court, saying they have raised questions on the functioning of Prime Minister's Office and the government.
The party also said it would raise the issue in Parliament.
Congress chief spokesperson Randeep Surjewala alleged that the DIG Manoj Kumar Sinha in his affidavit has named union minister Haribhai Parthivbhai Chaudhary, National Security Advisor Ajit Doval and Central Vigilance Commissioner K V Chowdhury over alleged attempts to interfere in the probe against CBI Special Director Rakesh Asthana.
K V Chowdhury did not respond to queries when his reaction was sought while Mr Doval, the National Security Advisor, was not immediately available for comments. An official in the minister's office said he was not aware of the matter.
Mr Surjewala asked Prime Minister Narendra Modi if his slogan of "na khaaoonga, na khaane doonga" (will neither do nor allow anyone to do corruption) has now changed into "sab khane walaon ko bachaoonga, aankh moondte dekhta jaoonga" (will save all the corrupt, will watch with shut eyes).
"Who are those helping the corrupt. Are those helping the corrupt sitting in the Prime Minister's Office," he asked.
"When IB, RAW and CBI's credibility is at stake, as it has been put at stake by words of this affidavit and when CVC responsible for investigating the entire matter, his own judgment and conduct is under a cloud, then democracy is in peril and Constitution is in danger," he told reporters.
"We definitely believe and we will appeal to the Court to conduct a separate investigation, if possible, otherwise we will go to the court of people. In democracy like ours, the final defender of peoples' right as also holding accountability of the Government is Parliament and we will go to Parliament," the Congress leader said.
The internecine feud in the CBI turned murkier Monday with a senior officer M K Sinha dragging the names of NSA Ajit Doval, union minister Haribhai Parthibhai Chaudhary and CVC K V Chowdhury over alleged attempts to interfere in the probe against CBI Special Director Rakesh Asthana, who has been divested of his duties and sent on leave along with his boss Alok Verma.
Mr Sinha, who was probing the FIR against Mr Asthana, the CBI's number 2, and important cases like the PNB scam involving Nirav Modi, made a litany of allegations in his petition before the Supreme Court that sought urgent hearing for quashing his transfer to Nagpur.