A Pakistani exotic animal dealer is battling to recover four lions which were impounded in Karachi Zoo after he had them flown in from South Africa.
Wildlife officials said it was illegal to import big cats and that the buyer, Irfan Ahmed, did not have valid import papers. He denies this.
The lions arrived in Karachi on Wednesday after being flown from Johannesburg to Frankfurt in November.
Zoos have often imported lions to Pakistan, where the cats are extinct.
Fahmida Firdous, chief conservation officer at Sindh province's Wildlife Department, told the BBC that Mr Ahmed's import permit had expired in June 2008.
"It has not been renewed since then. Besides, there has been a ban on the import of large wild cats since October 2008."
But Mr Ahmed, owner of Osaka Traders, which imports and exports animals and birds, told the BBC: "If I did not have the required documents, how could I fly these animals from South Africa to Germany and then to Pakistan?"
The dealer, who has previously imported elephants for Karachi Zoo, said he had not yet found a buyer for the big cats.
The BBC's Riaz Sohail in Karachi says there are several privately owned mini-zoos in Karachi, which might be interested in buying the animals.
Karachi Zoo already has an Asiatic lion, a subspecies thought to survive only in western India.