Opposition on Thursday raked up the Bofors issue in the Rajya Sabha alleging "cover up" in probe and "burial" of the case leading to acrimonious exchanges with the ruling alliance culminating in repeated adjournments.

The House was adjourned thrice in the pre-lunch sitting over former Swedish police chief's allegation that payoffs were made in purchase of Bofors guns during the tenure of then Prime Minister Rajiv Gandhi.

Raising the issue during Zero Hour, Leader of the Opposition Arun Jaitley said, "There were repeated efforts to cover up. The pace of investigation varied with the colour of the political government in power...we gave a whole burial to the case."

"....the fact is clear. Somebody got the contract and somebody got the kickback....this man (Ottavio Quattrocchi) is so powerful. Entire Indian state appeared so helpless....this is a textbook illustration of fraud," he said.

As Mani Shankar Aiyar (Cong) rose on behalf of the treasury benches to counter the allegations of Jaitely, Opposition members shouted him into silence asking why he is being allowed to speak when only leaders of parties in the House have been permitted to raise the matter.

Through a point of order, Najma Heptulla (BJP) demanded that Prime Minister Manmohan Singh, who is Leader of the Rajya Sabha, should be present if the House wanted a discussion.

Naresh Agrawal (SP) also raised objections to the Chair allowing Aiyar to speak on the issue saying this amounted to partiality and demanded everybody should be given opportunity to speak.

Noting that Jaitley has bemoaned the fact that unsuccessful efforts were being made to unearth the truth, Aiyar pointedly said, "The reason why we could not unearth the truth is because the pursuit of truth began with a series of untruths."

Aiyar also pointed out that no progress was made in the case from December 1989 to November 1990 (during VP Singh government) as well as NDA rule later.

Though Jaitely had not named the late Prime Minister maintaining that he did not intend to blame any political party or leader, Aiyar attacked him saying he has made serious allegations alluding to Rajiv Gandhi without directly naming him.

Aiyar said he has no problem in saying that the case belonged to a period when Rajiv Gandhi was the Prime Minster.

Jaitley said the fate of the case in which nobody could be nailed even after 25 years is a "serious reflection on the health of our investigating process" and stressed that there is a need to strengthen the capacity of institutions.

He said there was a need to introspect "where we had gone wrong" and "what is the capacity of Indian state and all agencies of our in pursuit of truth to find out where we have gone wrong.

Jaitley said "our neigbouring country in the western border" faced earthshaking consequences for a similar situation because the Government there did not take steps.

He emphasised that the middlemen must be eliminated and probity ensured in public life.

Joining the issue, Sitaram Yechury (CPI-M) said that the issue of Bofors has "plagued" the country for more than two decades.

"It has deeply impacted the country...the issue is of probity...even today there is a big question mark on defence deals. The whistleblower has formally said something.

Government must investigate it properly," he said.

Mohan Singh (SP) said the new facts must be investigated. It has given a chance to the country to bring the economic offender to the country for trial. He rued that the mystery over the corruption in Bofors was yet to be unravelled.

As the din continued, P J Kurien, who was in the Chair adjourned the House till 2 pm.

Earlier during Question Hour, the House was adjourned twice over the issue.

As soon as the House met for the day, BJP and AIADMK members displayed copies of a newspaper interview given by Swedish police chief Sten Lindstrom where he said Gandhi did nothing to prevent the cover-up to protect Quattrocchi, who is alleged to have received pay-offs in the case.

Every time BJP members shouted "Who saved Quattrocchi", ruling Congress members joined the chorus shouting "BJP ney bachaya (BJP saved him)".

Mani Shankar Aiyar (Cong) said Leader of the Opposition Arun Jaitely was the Additional Solicitor General who had done paper work in the Bofors investigation case.

Amid din, the House was adjourned for 15 minutes. As similar scenes prevailed when the House reassembled, it was adjourned till noon.