The Pakistan Tehreek-e-Insaf (PTI) has launched a legal battle against National Accountability (NAB) Chairman Lt-Gen (r) Nazir Ahmed.

On behalf of party chief Imran Khan, PTI lawyer Abuzar Salman Niazi has sent a legal notice of Rs15 billion damages to the NAB chief on the matter of his arrest.

According to the notice, Imran Khan's arrest warrant was issued on a public holiday (May 1) and it remained a secret for 8 days

It added: “Imran Khan was arrested by the Rangers on May 9 as a terrorist or a member of a banned organization.

“The arrest warrant was illegal under Section 24 of the NAB Ordinance and repeated notices were not sent as required by law.

"The inquiry was secretly converted into an investigation. According to section 13 of the NAB Act, it is necessary to inform the accused while converting the inquiry into an investigation

It continued: "The Supreme Court in its decision declared Imran Khan's arrest illegal and unconstitutional. NAB chairman violated Imran Khan's fundamental constitutional rights.

"He deliberately took illegal action which shows his malice. The NAB chief should immediately apologise to the PTI chairman and pay Rs15 billion as compensation

"If he does not apologize, legal action will be taken."