BEIJING - Photos of an elaborate, but illegal garden built atop a 26-story building in downtown Beijing have been feverishly shared and forwarded online since Monday.

The urban management bureau of Haidian District on Monday deemed the man-made rooftop oasis as a piece of illegal construction. They posted a notice on the door to the apartment the same day, urging the builder to dismantle it within 15 days starting Monday.

A privately built villa, surrounded by imitation rocks, is pictured on the rooftop of a 26-story residential block in Beijing, August 13, 2013. [Photo/Agencies]

Photos show the top of the 26-story building covered in a man-made mound dotted with artificial rocks, greenery and a swimming pool.

The bureau on Tuesday confirmed that the villa was built by a man named Zhang Biqing, the owner of the duplex penthouse on the top floor of the building.

According to property management staff of the Park View residential community, Zhang has paid the property management fees for his apartment, which had a floor space of more than 340 square meters before the roof-top villa was built.

Neighbors have long complained that the construction of the villa, which started in 2007, has caused gas and water leaks that have affected several apartments on lower floors. They are also concerned about potential safety hazards brought on by the construction.

A manager of the building's property management company acknowledged that the company has known about the project, but that further action would require law enforcement power that it simply does not have.

The property management company and urban management staff have both failed to reach Zhang.

Local newspapers and other media have identified the owner of the apartment as Zhang Biqing, a wealthy Chinese medicine practitioner known for his therapies for treating difficult illnesses, such as cervical spondylosis.

However, urban management officials have yet to confirm these reports.