Aiming straight at the Congress' top leadership the minister said in his reply to the Rajya Sabha debate, "It appears an invisible hand was guiding the action or inaction of CBI and ED...the country wants to know who instigated, supported and benefited from corruption. We can't let this pass."

Questioning decisions taken by the then Congress government that led to a deal with Anglo-Italian firm AgustaWestland for 12 helicopters, Mr Parrikar said the Italian court had in its recent verdict said "there is proof of mala fide intent."

A furious Congress clashed repeatedly with the BJP and walked out of the House when the government rejected a demand of most opposition parties that the CBI investigation to find out who in India received bribes in the Agusta scam be monitored by the Supreme Court in a time-bound manner.

"Take strongest action against whoever took money. Prosecute us if you have evidence, but don't threaten, blackmail us." said former Defence Minister AK Antony of the Congress, rejecting the BJP's allegation that Congress leaders had colluded with AgustaWestland.

An Italian court - which concluded last month that bribes of up to 30 million euros or Rs 226 crore were paid in India for the chopper deal - had referred in its verdict to documents which mention Congress president Sonia Gandhi and other leaders of her party, though they have not been indicted by the court for corruption.

The BJP's Subramanian Swamy alleged there is evidence to prove that Mrs Gandhi was a principal player in the scam and said she "should be interrogated first by the CBI." The known Gandhi family baiter did not name the Congress president.

Mr Swamy demanded that former Prime Minister Manmohan Singh's statement be recorded and also said, "I think Dr Manmohan Singh was overruled by the 'Super PM'," in a pointed reference to Sonia Gandhi, as the Congress benches erupted in protest.

"He suffers from an obsession," said the Congress' Anand Sharma in reference to Mr Swamy, and also, "It reveals your twisted mindset. It is diabolical. I cannot come down to your level."

Ahmed Patel of the Congress made a rare speech saying, "If you find an iota of truth in Agusta allegations I will resign and quit public life." The documents referred to by the Italian court mention the initials "AP," which the BJP alleges refers to Ahmed Patel.