ISLAMABAD: Pakistani authorities arrested a media mogul on corruption charges Thursday, in a decades-old case his representatives said was motivated by a desire to retaliate following the broadcast of several investigative programmes.

The National Accountability Bureau (NAB) arrested Mir Shakeel-ur-Rehman - the editor-in-chief of the Jang Group that includes some of Pakistan's biggest newspapers and the Geo television network - over a land transaction dating back to 1986, accusing him of scoring illegal concessions in the purchase of plots in Lahore.

In a statement, Geo denied the allegations against Rehman, saying all taxes and legal requirements pertaining to the property purchase had been fulfilled.

Geo said the NAB only arrested Rehman because of investigative pieces his channels had conducted into the bureau.

Over the past 18 months the NAB has "sent our reporters, producers and editors - directly and indirectly - over a dozen threatening notices," the statement read, adding that the bureau had said it would shut down "our channels... due to our reporting and our programmes about NAB".

"In its defence, NAB has in writing said it is a constitutionally protected institution that can't be criticised," the statement continued.

Pakistani media have been subjected to growing censorship and pressure following the election of Prime Minister Imran Khan in 2018.

The NAB was founded in 2000 by then military ruler Pervez Musharraf to go after corrupt politicians, bureaucrats and businesspeople.

However, it came under fire after Khan was elected, with leading opposition parties accusing it of being used for political ends.

In recent years the space for dissent has shrunk further in Pakistan, with the government announcing a crackdown on social networks, and traditional media houses decrying pressure from authorities that they say has resulted in widespread self-censorship.