As of Aug 4, 258 Beijing buildings with unauthorized parts have been prevented from being transferred and mortgaged this year, Beijing News reported on Tuesday.

A city official said the buildings were mostly private villas or bungalows that were rebuilt or expanded without authorization.

Once buildings are found to have unauthorized parts, city officials will inform the local housing authorities not to transfer and mortgage, and the buildings will be unfrozen only after the unauthorized parts are removed, the official said.