BEIJING - At least 50 young students were unwitting advertisers for a real estate company in North China's Inner Mongolia autonomous region, after their good performance was rewarded with a new uniform bearing the firm's name.

The Baotou No 24 Middle School gave the students in the second and third grades a new red uniform. On the back were words saying they were good students and the name of the uniform's sponsor, Xiangrui Real Estate Co.

Only students with good performance or improvements in their studies were allowed to wear the red uniform on campus. The other students wore the usual blue, white and black uniforms.

The news was published by an Internet user named TianyouzhonghuaA on a micro blog on Tuesday.

The Net user also posted a photo that showed the writing on the back of the uniform.

TianyouzhonghuaA described such advertising as overly "money-oriented" and "a sick phenomenon".

The micro blog was forwarded nearly 2,000 times on Sina Weibo, China's equivalent of Twitter, within 24 hours. It sparked a heated debate among Net users, a few of whom apparently did not mind advertising on school uniforms.

Education officials, however, did mind.

"We heard the news (on Tuesday) morning, and we launched an investigation to figure out whether it was a routine award or a business activity," Gao Jiuan, chief of the Baotou education bureau's publicity office, told China Daily on Wednesday.

He said school officials were to blame for the practice.

"I support the school's measure to encourage outstanding students if it was without any commercial intents," he said.

The Donghe district education bureau, which is responsible for Baotou No 24 Middle School, asked the school to recall the red uniforms within a week, Xinhua News Agency reported.

The school leaders were ordered to provide an explanation and a self-criticism to the education authority, and to explain the situation to parents.

This was not the first time that linking school uniforms to students' performance has sparked controversy.

In a recent case, the No 1 Experimental Primary School in Weiyang district, in Xi'an, capital of Northwest China's Shaanxi province, required poorly performing students to wear green scarves instead of the usual red. After an outcry, the practice was ended.

A primary teacher in Beijing's Shijingshan district, who declined to be named, said students uniforms should not be linked to their performance.

"It is not a good way to teach children how to face honor and failure, and sometimes it is a gross violation of personal dignity," she said.

The Baotou No 24 Middle School refused to comment, and Xiangrui Real Estate Co could not be reached.