The alleged swoop on his publisher by the Inter-Services Intelligence (ISI) agency comes months after the long-awaited translation of his 2008 novel "A Case of Exploding Mangoes" went on sale in Pakistan -- more than a decade after its English-language debut.

The book chronicles the final days of hardline dictator General Zia-ul-Haq and the myriad conspiracy theories behind the plane crash that killed him in 1988, while also harshly criticising Pakistan's military establishment.

In the book, the military relies on torture and extrajudicial murder, and covertly supports a jihadist insurgency to pursue its goals -- accusations made by rights activists in real life, but which the military denies.

"This afternoon some people claiming to be from the ISI barged into my Urdu publisher Maktaba Daniyal offices," Hanif tweeted late Monday, adding they "confiscated all copies of Urdu translation of A Case of Exploding Mangoes".

He said they had "threatened the manager" and "wanted information about our whereabouts".

Hanif's novel earned glowing reviews and was longlisted for the Booker Prize, with critics comparing him to satire writers such as Joseph Heller and Kurt Vonnegut.

Despite the widespread praise -- and its availability in English in Pakistan -- more than a decade passed before the book was translated into Urdu.

"A Case of Exploding Mangoes has been in publication for 11 years now. Nobody has ever bothered me. Why now?" tweeted the author.

"I am sitting here, wondering when will they come for us."

The military had no immediate response to Hanif's claims, but bookshops in Lahore and Islamabad said Tuesday they still had Urdu versions on sale.

Works written in English have a narrower, elite audience in Pakistan and often have greater leeway, but Urdu content tends to be more carefully censored.

Hanif, who graduated from the Pakistan Air Force Academy as a pilot officer, later became a journalist before also turning to writing novels.