Adviser to the Prime Minister on Parliamentary Affairs Babar Awan resigned from his post on Tuesday in wake of the corruption reference filed against him by the National Accountability Bureau (NAB) for allegedly causing delays in the Nandipur Power Project.

According to the reference filed in the Accountability Court, the bureau holds Babar Awan — who was the federal law minister in the PPP government — responsible for delaying the power project while in office.

PPP's Raja Pervez Ashraf, who was the federal minister for water and power at the time, has also been named in the NAB reference.

Tweeting about his resignation, Awan said that he prefers to resign rather than staying put in his official position. He added that he would fight the case in the court of law to prove his innocence.

"Just reached PM House to tender my resignation from Ministry of Parliamentary Affairs. Rule of Law begins with me. Thank you, Insafians for standing by me always. I will never let you down," he tweeted.

The PTI leader forwarded his resignation to Prime Minister Imran Khan.

The NAB has claimed that the Ministry of Water and Power and the Ministry of Law and Justice were responsible for the delay in the completion of the Nandipur power project and for its eventual cost escalation.

The law ministry had raised objections to the agreement signed by the power ministry from 2008 to 2011 and the issue was resolved after the ministers for the two ministries were removed.