Iranian police have arrested the head of a real estate agency after a viral video showed his firm selling an apartment to a dog, officials said on Sunday. 

In the video, which spread widely over the weekend, an Iranian couple signed a contract transferring title of their apartment to their furry, white, small-breed dog. 

The animal, named "Chester", placed its paws on an ink pad with the help of a woman before the contract was stamped. 

She said in the video that the couple had no "heirs and that they wanted to sell the apartment to the dog."  

There is no law banning dog ownership in Iran but, as in many Muslim countries, they are considered unclean. Conservative clerics have advised against keeping them as pets.

On Sunday, ISNA news agency reported that the "police launched an investigation" following the video. 

"The police arrested the head of the real estate agency and shuttered the firm on Saturday," the judiciary's Mizan Online website said, quoting deputy prosecutor general Reza Tabar. 

Tabar said the sale seeks to "normalise the violation of the society's moral values", and has "no legal basis".

Mizan did not identify the arrested realtor.

Many Iranians, especially among the upper and middle classes, have in recent years embraced the trend of pet ownership, usually dogs and cats. 

ap/mz/it