Punjab Government spokesperson Malik Ahmed Khan on Thursday warned Pakistan Tehreek-i-Insaaf (PTI) Chairman Imran Khan with a lawsuit, giving him three days to reveal the identity of the person who allegedly offered Khan a Rs10 billion bribe to keep mum on the Panama papers scandal.

In a video leaked to social media websites earlier this week, PTI chairman Imran Khan could be heard alleging that the large offer was made through a 'middle-man' who he refused to name.

Explore: Imran’s bribery allegation stirs up a hornet’s nest

"Just imagine how much money he offered me to be silent. Rs10 billion. If he can offer me this much money, just imagine how much he would offer to others. That is why if we don't maintain public pressure on this issue, then after two months it will be dragged to next year," Khan appears to be saying in the video.

Maryam Nawaz Sharif was quick to discredit Khan's claims in a one-word tweet, calling him a "liar".

Today's decision by the Punjab government indicates a shift in the ruling party's approach to dealing with Khan's slanderous claims.

“If Imran Khan does not provide the name in three days, we will file a defamation notice and a claim in a court of competent jurisdiction,” the Punjab government spokesman warned.

Speculation has been rife over the identity of the man who is said to have made the Rs10bn offer, or if there was one at all, with some commentators demanding that it is squarely in the public's interest to know who the person offering the bribe was and whether there is any merit to Khan's claims at all.

Surprisingly, PPP leader Nabil Gabol claims to 'know' who the person is.

Talking to a private news channel, PTI's Asad Umar said Khan should never have spoken about the offer without having consulted the person who made it beforehand. However, he too said he 'knows' who the person in question is.

This is not the first time Imran Khan has been threatened with a lawsuit. In October 2016, Punjab Chief Minsiter Shahbaz Sharif filed a Rs26bn defamation lawsuit against Imran Khan.