Shimla, Aug 6 - Congress legislators Thursday stalled the proceedings of the Himachal Pradesh assembly and staged a walkout over the government's clarification over the corruption cases filed against union Steel Minister Virbhadra Singh and his wife Pratibha Singh.

Raising the issue after question hour, Leader of Opposition Vidya Stokes asked Chief Minister Prem Kumar Dhumal to clarify his statements to the media that he had no information about the registration of the case against Singh and his wife.

She alleged that the government was being vindictive against the opposition.

'I can't say whether it was (the registration of the case) out of vengeance or not, but it has surely been done for political gains as the by-elections to the two assembly seats in Himachal Pradesh are around the corner. The BJP government has not been fair to us,' Stokes said.

Replying to Stokes' charges, Dhumal denied there was 'any political move' in it and said the law should be allowed to take its own course.

Dhumal gave a detailed reply about the case's process from the day an audio-CD was released by former Congress minister Vijai Singh Mankotia May 28, 2007, and a vigilance inquiry ordered into the matter by the then Congress government.

He said when the Bharatiya Janata Party (BJP) government assumed office in December 2007, there were complaints that there was no progress in the vigilance inquiry.

'On May 2, 2008, the statement of former IAS (Indian Administrative Service) officer Mohinder Lal was recorded and on May 7, 2008, statement of former IAS officer S.M. Katwal was also recorded. Following this, the CD was sent for authentication of voices at Central Forensic Science Laboratory in Chandigarh.