With the police registering a case of criminal conspiracy and forgery into the phone tapping allegations, the Samajwadi Party on Saturday demanded a Joint Parliamentary Committee probe into the matter.

"We want a JPC probe into the matter," SP General Secretary Ramgopal Yadav, brother of Uttar Pradesh [Images] Chief Minister Mulayam Singh Yadav [Images], told reporters when asked if the party will seek a Central Bureau of Investigation inquiry into the allegations.

Mulayam Singh Yadav had on Friday accused Congress president Sonia Gandhi [Images] of ordering tapping of telephones of senior SP leaders as part of attempts to topple his government, which the Congress immediately rejected as 'baseless and unwarranted'.

Ramgopal Yadav said the party will move the court in the matter and also approach the Privilege Committee in Rajya Sabha to verify the authenticity of the charges.

He said Mulayam Singh Yadav will release detailed documents, particularly the two letters by Delhi [Images] Chief Secretary Narayan Swami and Delhi Police Joint Commissioner (North) Ranjit Narayan to a nodal officer in this regard.

He alleged that the Delhi chief secretary had written a letter on November 9 to a nodal officer to tap certain phone numbers allotted to the SP General Secretary Amar Singh [Images] for national security and to check kidnapping, murder, robbery and report all developments to the JCP (North).

The JCP (North) also wrote to the nodal officer on October 22 asking him to divert 'all incoming and outgoing' phone calls on the particular number to him for safety reasons, he claimed.

Drawing a parallel with the Watergate scandal in which US President Richard Nixon was forced to resign, he said 'misuse' of government machinery by an 'extra-constitutional authority' against political adversaries was against all norms.