A number of employees of a south China factory have been fired after refusing to sign guarantees in which they have to declare they are "sons of a beast" if they break their commitments to the company, reported Guangzhou-based Yangcheng Evening News.

The company in Shenzhen city, whose name was not fully revealed in the newspaper report, requires it employees to sign written pledges that contain more than 30 articles including "loyalty to the factory" and "be respectful to superiors."

The fifteenth article has caused the most controversy. It requires applicants to swear that if they break any of the articles they are "chu sheng" or 'born by a beast' which usually refers to a farm animal. The curse is serious in Chinese language.

More than 200 workers at the factory have signed the pledges.Those who have refused to sign have been fired. The newspaper didn't report how many workers have lost their jobs.

According to China's labor Law, employers and employees enjoy equal status. Lawyers say that the "s.o.b. article" humiliates employees and they should complain to labor authorities.

A senior official at the factory was quoted as saying that he is not sure of relevant legal regulations, but was willing to revise the article.